Your July Statistics

[Optimus Prime]

A pretty cool month overall with some unusually chilly nights for the time of year at times. Despite this, it was a pretty decent month.

Mean maximum 21.7c (-0.5c) coolest since 2007 at 20.9c

Mean minimum 11.7c (-1.2c) coolest on record since 2003 (2007 recorded 12.0c)

Mean 16.7c (-0.8c) coolest since 2007 which recorded 16.4c

Highest maximum 25.1c (5th)

Highest minimum 14.3c (12th)

Lowest maximum 17.7c (18th)

Lowest Minimum 7.7c (24th)

[TonyH]

July 2011, Llanwnnen, Lampeter

Near average rainfall and temperatures; driest since 2006

Overall a fairly 'typical' July, if such a thing exists! Both overall temperatures and total rainfall being very close to average. In finer detail, the month was often unsettled for the first 22 days, then mostly dry; a high frequency of cool nights (8 getting lower than 8c), and a lack of heat throughout the month with 25c not being reached. A high incidence of fog -7 days - but this perhaps more of a reflection of the fact that I now have a webcam and can view snapshots of pre- dawn and early morning mist and fogs, whereas in previous Summers, my slumbers meant I remained blissfully unaware of them!

1^st –4^th: A warm, sunny start to the month but with very chilly nights in the 3-6c range, and close to ground frosts.

5^th –10^th: Unsettled with rain or showers, some heavy, also sunny spells. Rather windy with near average temperatures.

11^th –14^th: Mostly dry and rather warm, sunny at times. Thundery showers passed close by on the 12^th but we escaped with just trace rainfall. A very cool mid July night, minimum 3.8c on the14^th.

15^th-22^nd: Very unsettled, often cool and breezy. Generally cloudy with spells of rain and showers, these very heavy at times. 21.6mm on the 21^st made it the wettest day since February (this however showing the dryness of 2011 to date and lack of really wet days).

23^rd-27^th: Dry and became warm. A mix of cloudy and sunny periods with the north-west flow about the high to the west. Plenty of early morning mist and fog, some nights being very cool once more.

28^th –31^st: A mostly cloudy, rather warm and humid end to the month. Some bright spells but also a little light rain or drizzle attimes.

Stats

Total Rainfall: 88.4mm

Wettest day: 21.6mm 21^st

Rain days>0.2mm: 15

Wet days >1.0mm: 11

Days of heavy rain>10mm: 3

Mean Temperature: 14.8c

Mean Max: 20.0c

Mean Min: 9.6c

High Max: 24.4c 4^th

Low Max: 14.4c 18^th

High Min: 14.5c 31^st

Low Min: 2.9c 2^nd

Air frost: 0

Ground frost: 0

Mean RH: 80%

High RH: 96% various

Low RH: 43% 4th

Predominant wind directions: WNW and SSE

Mean wind speed: 1.2mph

Mean pressure: 1012mbar

Max pressure: 1028mbar 1^st

Min pressure: 989mbar17^th

Days with:

Hail:0

Gale: 0

Thunder: 1

Fog: 7

Fog at 0900: 0

Adjustments have been applied to some maxima of 1c which is not apparent in the graphs

Edited August 1, 2011 by Tonyh

[Teesdale]

Best July weatherwise since 2006, some nice warm sunny days and much drier than recent July's

Mean max 17.3C

Mean min 8.4C

Mean 12.9C

Rainfall 76.4mm

Highest max 21.5C

Lowest max 13C

Highest min 11.6C

Lowest min 5.2C

[The PIT]

Yet another very dry month with less than 50% rainfall. Slightly below average temp wise however this hides the fact that some days were cool and only a brief burst of sun brought the temps up towards normal.

Average max 20.5C

Average min 11C

Overall -0.4C below normal

Rainfall 23.5mm 47.5% of average.

Nearly got a ground frost on two nights 1.9c on the 23rd and 1.7c on 30th

Full details http://www.sheffieldweather.co.uk/Weather%20Data.htm

Quick summery http://www.sheffieldweather.co.uk/Last%20Months%20Report.htm

Edited August 1, 2011 by The PIT

[Static Prevails]

Mean maximum- 20.2°C

Mean minimum- 11.0°C

Mean- 15.7°C

Highest maximum- 24.4°C

Lowest maximum- 16.7°C

Highest minimum- 15.0°C

Lowest minimum- 7.1°C

Rainfall- 26.7mm

Overall, a cloudy, cool, and dry month, with the odd one or two decent days thrown in. The mean was around 1°C below average, as were the mean maximum and minimum temperatures. The month was very dry, with less than 50% of the average rainfall. The month never reached 25°C, which was disappointing. June, overall, was better.

[Stargazer]

From just down the road from OP...

Central Reading, July 2011

Average maximum: 21.3

Average minimum: 12.4

Average for month: 16.8

Highest maximum: 25.6 (July 5)

Lowest maximum: 17.6 (7)

Highest minimum: 16.0 (31)

Lowest minimum: 9.4 (22)

No ground frosts or thunder recorded.

Rainfall: no data available for this site; Reading University shows around 35mm for the month, which is slightly below average.

A cooler than average month overall, characterised by an abundance of showers but little prolonged rain. Some warm days at the beginning and end of the month but two runs of cool and showery weather in between.

[J10]

A better July than recent years, but in a way split into 2, the first half of the month, it seemed the weather gods were smiling on us. The start and the month as with the end of June was dry settled and quite warm with plenty of sunshine. It turned unsettled from the 5th with some heavy showers, but these tended to be in the morning with some sunny spells pm. It dried up to give a very nice weekend on the 9th/10th.

The next week was mainly dry apart from a heavy shower late on the Tuesday (12th), with decent amounts of sunshine and again fairly warm, which takes us to mid month. Reading this back has made me realise how nice the first half of July was.

The Weekend of 16th and 17th was rather unsettled, a mix of sunshine and heavy showers. After this a unsettled week with some heavy showers and some sunny intervals, but less sun than the corresponding unsettled period 5th-8th in the start of the month.

The weekend of 23rd and 24th was mixed, the Saturday was largely sunny but the Sunday was cloudier than expected. The final week of the month was largely dry with Tuesday pm (25th) and Wednesday (26th) until around 2pm, completely sunny with cloud at other times. The remainder of the days started cloudy but with some sunny intervals developing for a couple of hours during the afternoon and feeling warm when it did. But given the relatively settled pressure for the last week, the relative lack of sunshine was a bit of a disappointment, especially on the Sunday 31st.

Local weather station averages 16.0c, with Max 18.8c, Mins 13.2c

Rainfall local weather station 77mm, with 12 of more than 1mm rain.

http://www.metoffice.gov.uk/climate/uk/anomacts/ July Stats now out

http://www.metoffice.gov.uk/climate/uk/anomacts/2011/7/2011_7_Sunshine_Actual.gif around 200 hrs sun here.

[Kiewii]

Its been a slightly warmer month than June.

Kirriemuir, Scotland.

In brackets are the data for the previous month.

High: 22.1C (24.5C)

Average Temperature: 14.1C (11.4C)

Low: 3.7C (3.4C)

Sunshine Hours:

161 hours (150 hours)

Rainfall:

Most in 1 day: 77.4mm - 6 July

Month: 146.3mm (87.4mm)

Wind Speed:

Average: 4 mph (6 mph)

Gust: 39 mph (48 mph)

Humidity:

High: 100% (100%)

Average: 89% (86%)

Low: 42% (41%)

Pressure:

High: 1028mb (1037mb)

Average: 1010mb (1010mb)

Low: 982mb (996mb)

[Snowstorm1]

Highest Temp 26.9C

Lowest Temp 9.8C

Average Temp 16.4C

Edited August 2, 2011 by Snowstorm1

[Robbie Garrett]

MAX 25 °C

Min Temperature 16 °C

Precipitation 28.40 mm

Average Mean 17 °C

Edited August 3, 2011 by Robbie Garrett

[Aaron]

July 2011

Mean max: 19.0°C

Mean temperature: 14.8°C

Mean min: 9.5°C

Highest temperature: 25.2°C

Low temperature: 7.0°C

Highest dew point: 15.3°C

Lowest dew point: 1.7°C

Days above 20°C: 11

Days above 25°C: 2

Nights above 15°C: 0

Nights below 10°C: 11

Highest minimum: 14.0°C

Lowest maximum: 14.5°C

Average humidity: 74%

Highest humidity: 97.3%

Lowest humidity: 30.8%

Rainfall: 35.8 mm

Days with measurable rain: 14

Most rain in 1 day: 5.1 mm

High pressure: 10126.3 mb

Low pressure: 986.0 mb

Average wind speed: 4.5 mph

Highest wind gust: 22 mph

Highest sustained wind speed: 13 mph

Days with thunder: 2 (thundery showers)

Days with lightning: 2 (thundery showers)

Thunderstorms: 0

Overall, it was a cooler than average month, particularly the mean minimum temperature. It was, however, drier than average. A lack of thunderstorms too, not just July but the entirety of 2011.

Edited August 3, 2011 by aaron

[Andy Bown]

A cooler July than most I have recorded since beginning recordings in 2003. There were many maximums between 20c-23c and many

minimums between 11c-13c. A wet month with nearly 100mm, over half of which fell on 2 very wet spells (6-7 July & 16-17 July).

For Warminster, Wiltshire

Average max = 21.31c (Highest = 26.6c on 4 July)

Average min = 12.47c (Lowest = 8.5c on 14 July)

Mean - 16.89c

Dry days = 15

Rain days = 16

Rainfall = 97.5mm

[Evening thunder]

Quite a cool month overall with below average temps, rain and sunshine. There were several dull damp cool days but not actually giving much rain. However There were also some decent summery days/spells like at the beginning of the month (with notably cool nights and average days, porobably some days 11th-14th though I was away then, and near the end of the month where the warmest weather occurred. The lowest min and by far the lowest max are the lowest I've recorded so far although only 4 July's data now.

Stats from my station below. Note data recorded midnight-midnight GMT except highest/lowest overnight temps which are corrected for the overnight period.

Highest Max: 24.3°C ( 25th)

Lowest Max: 14.9°C (18th)

Highest Min: 15.0°C (28th)

Lowest Min: 4.9°C (1st)

Highest Daily Mean: 18.8°C (25th + 28th)

Lowest Daily Mean: 12.8°C (1st)

Mean max: 20.0°C

Mean min: 10.1°C

Mean: 15.4°C

Wettest Day: 8.4mm (6th)

Monthly Total: 29.8mm (a bit below average)

Days of rain >1mm: 8

Highest Gust: 34mph (6th)

Average wind speed: 4.3mph

Temp, Dew point, Daily rain: Pressure, avg. wind speed, daily top gust:

Edited August 4, 2011 by Stormmad26

[johnholmes]

here and its better than a couple of previous July's but not by much. Temperature around average but dry.

Temperatures in degrees C with long term averages in brackets

Mean=16.9(16.2)

Mean Max=22.2(21.0); warmest=28th with 27.3 and coldest day=13th with 17.5

Mean Min=11.6(11.5); coldest night=31st with 8.7 and warmest night=4th with 14.5

Rainfall=20.9mm(47.7) wettest day=20th with 6.6mm; 02.mm or more on 11 days and 6 days with 1.0 mm or more

No fog, thunder, frosts or hail

[reef]

here and its better than a couple of previous July's but not by much. Temperature around average but dry.

Temperatures in degrees C with long term averages in brackets

Mean=16.9(16.2)

Mean Max=22.2(21.0); warmest=28th with 27.3 and coldest day=13th with 17.5

Mean Min=11.6(11.5); coldest night=31st with 8.7 and warmest night=4th with 14.5

Rainfall=20.9mm(47.7) wettest day=20th with 6.6mm; 02.mm or more on 11 days and 6 days with 1.0 mm or more

No fog, thunder, frosts or hail

Thats a remarkably high mean max there John, almost 3 degrees higher than here. Have you considered adding a daytime FARS unit to your Davis?

[reef]

Hedon, East Yorkshire.

July 2011

Warmest Max: 24.4°C (on 15/07/11)

Coldest Max: 15.9°C (on 13/07/11)

Warmest Min: 14.3°C (on 06/07/11)

Coldest Min: 8.3°C (on 01/07/11 & 31/07/11)

Average Max: 19.4°C (-1.6°C Below 1971-2000 Average)

Average Min: 11.6°C (-0.7°C Below 1971-2000 Average)

Overall Average: 15.5°C (-1.2°C Above 1971-2000 Average)

Rain: 33.8mm (88% Of Normal)

Wettest Day: 8th (7.6mm)

Sunshine: 177 hours (93% Of Normal)

Air Frosts: 0

Sleet/Snow Falling: 0 days

Snow lying at 0900: 0 days

Dry Days: 15

Wet Days: 16

Days With Rain >1.0mm: 8

Thunderstorms: 6

Year 2011 So Far (Jan - Jul)

Warmest Max: 29.7°C (on 27/06/11)

Coldest Max: 2.2°C (on 03/01/11)

Warmest Min: 16.5°C (on 27/06/11)

Coldest Min: -3.3°C (on 21/01/11 & 29/01/11)

Average Max: 14.0°C (+1.0°C Above 1971-2000 Average)

Average Min: 6.8°C (+1.1°C Above 1971-2000 Average)

Overall Average: 10.4°C (+1.0°C Above 1971-2000 Average)

Rain: 192.0mm (62% of Normal)

Wettest Day: 05/02/11 (11.6mm)

Sunshine: 1101 hours (118% of Normal)

Air Frosts: 12

Sleet/Snow Falling: 3 days

Snow lying at 0900: 0 days

Dry Days: 90

Wet Days: 121

Days With Rain >1.0mm: 50

Thunderstorms: 15

The coolest July since 2000 and 4th coolest in the last 30 years. It was the third July in the last 5 years which failed to reach 25°C. For such a cool month, it was actually quite dry, with only 2006 and 2010 being drier in the last decade. It was however slightly duller than average, beating last July by only 7 hours and the 3rd dullest of the last decade. Perhaps most notable was the lack of warm nights. The high minima of 14.3°C was the lowest on record. Only 6 days recorded minima of 13°C or more. The mean min temp was just 0.3°C short of the low record.

The month started off on a settled note with warm days but it quickly became wetter and more unsettled from the 5th. It also turned much cooler, only 4 days reached 20°C after the 11th with winds frequently from the north. The 17th saw an air pressure reading of 985.3hPa, a notably low value for July and the lowest since at least 2000. There were also some notably cold nights, with the 1st and 31st being just 1.4°C short of the record and the coolest nights in July since 2001. The final 10 days were then much more settled and no measurable rain was recorded. They were very cool however, with a mean of just 14.8°C. Unsuprisingly this lead to the first half of the month being warmer than the second.

Overall, a rare combination of a cool month with regards to temperature but close to average in sunshine and rainfall levels.

[johnholmes]

Thats a remarkably high mean max there John, almost 3 degrees higher than here. Have you considered adding a daytime FARS unit to your Davis?

nope too expensive but I am thinking of getting an old fashioned thermometer to do checks. I suspect its days of high sunshine levels especially mid to late afternoon that are some of the cause but why its showing now I'm not sure. I usually compare my absolute max values with 3 other stations in the vicinity, one an accepted Met O climat site, and 1 other is a COL site. I've not checked the June data yet but will be doing this week and I'll post the result back in here.

The checks over the last few days of a site about 3 miles away suggests we are within about 1C of each other most days, sometimes one higher sometimes the other. For July and the values are again within 1C.

Looking at the COl data forJune, July will not be available for a little while yet, the 2 stations along with mine, one appears obviously in error, maybe just a typing error, my abs max was 32.9C on 27th, the other was 32.4C same day; the 3rd showed 21.7C but an avge max similar to mine and the other one; the avge max from all 3 is withing 0.4C, mine being the higher one, so nothing really to suggest in that month or any other month that I have a problem with the max temps I post. I already do a quality check each day before accepting Davis data.

Maybe? this small area has had higher values but I'll post back in here once the July data is in.

Edited August 8, 2011 by johnholmes

[Radiating Dendrite]

Thats a remarkably high mean max there John, almost 3 degrees higher than here. Have you considered adding a daytime FARS unit to your Davis?

I agree.

I think the same thing occured in June also.

[Zenarcher]

Castlebay Isle of Barra July 2011

Highest Temperature 18.6°C

Lowest Temperature 8.9°C

Average Temperature 12.4°C

Total Rainfall 50.8mm

Highest Humidity 97%

Lowest Humidity 58%

Average Humidity 84%

Highest Average Wind Speed 48mph

Average Wind Speed 14mph

Highest Gust 58mph

Highest Pressure 1028mb

Lowest Pressure 1000mb

Lowest Wind Chill 2.5°C

Highest Dew Point 14.4°C

Lowest Dew Point 6.7°C

Average Dew Point 11.3°C

[johnholmes]

I agree.

I think the same thing occured in June also.

I have replied earlier and made comment about the values.

Having got the COL official data for June I show it here for comparison.

Auckley Absolute Max(about 1.5 miles away from me)=32.4C mine was 32.9C both on 27 June.

His avge max was 21.0C mine was 21.4C.

Another observer with similar status to the Auckley one also recorded 21.0C as the mean max. His absolute max obviously has an error as it was reported as 21.7C, perhaps it should have been 31.7C but I have not seen a correction yet.

Thus for June at least my max values seem in line with 2 other stations within 1.5 to 3.5 miles from me!

Other relevant comments from the June COL issue for this or close by areas

Auckley commented it was the highest June value since 1992

Ashover(edge of Peak District)500ft+ height=28.6C highest since 29.5C 19/06/05

Louth=31.8C

Hull-north=31.9C the 3rd highest ever since started in 1989

Collingham-?=32.2C highest since before 1962

Whitby=30.7C the highest ever in its 34 year history.

As I've suggested before my temperature max is, in my view, within 0.5C of previously tested NPL checks, so I think perhaps this area does have a bit of a micro climate of its own in certain synoptic situations that favour high temperatures for this area. It is of course possible that the Davis thermometer sensor has drifted off but a bit unlikely in my view.

I understand your scepticism of my figures though but I do, as a retired professional who once had the task of checking such figures, believe my max temperatures are not as far out as you appear to imply-rest assured they are kept under close scrutiny!

Edited August 13, 2011 by johnholmes

[Thundery wintry showers]

I note that all three of the COL sites in Doncaster are graded "C2", implying sheltered exposure, which tends to result in inflated maxima in the summer, particularly on sunny days. The three sites' readings are remarkably consistent, but the question is, are they consistently representative of the "true" values, or consistently inflated due to each having similar exposure issues? For this reason I maintain some scepticism.

[Bottesford]

July 2011 near city centre Nottingham

Maximum temperature: +26.2 °C at 14:10:00 on 05 July

Minimum temperature: +10 °C at 05:38:00 on 01 July

Maximum barometric pressure: 1017 mB at 11:25:00 on 01 July

Minimum barometric pressure: 979 mB at 19:55:00 on 17 July

Average temperature: +17.6 °C

Average maximum temperature: +22.1 °C

Average minimum temperature: +13.1 °C

Average barometric pressure: 1002.9 mB

Average maximum barometric pressure: 1005.6 mB

Average minimum barometric pressure: 1000.2 mB

Rainfall summary:

5th July - (1 mm)

6th July - (1 mm)

8th July - (14 mm)

10th July - (2 mm)

16th July - (11 mm)

17th July - (2 mm)

18th July - (4 mm)

19th July - (3 mm)

30th July - (1 mm)

Number of rainfall days: 9

Maximum rainfall rate: 27 mm/hour at 17:55:00 on 08 July

Total rainfall for July: 39 mm

[MP-R]

I note that all three of the COL sites in Doncaster are graded "C2", implying sheltered exposure, which tends to result in inflated maxima in the summer, particularly on sunny days. The three sites' readings are remarkably consistent, but the question is, are they consistently representative of the "true" values, or consistently inflated due to each having similar exposure issues? For this reason I maintain some scepticism.

That's exactly what happens here sometimes. Surrounded by hills to my north, east and south, we often get higher maxima in summer, especially in muggy SWerly flows and dry Erly flows than say Martyn Hicks' weather station in Bristol.

Then on normal days we are both within 0.5-1C of each other. It's useful having a relatively close weather station to compare.

[johnholmes]

I note that all three of the COL sites in Doncaster are graded "C2", implying sheltered exposure, which tends to result in inflated maxima in the summer, particularly on sunny days. The three sites' readings are remarkably consistent, but the question is, are they consistently representative of the "true" values, or consistently inflated due to each having similar exposure issues? For this reason I maintain some scepticism.

The question is really one of how representative are sheltered garden sites of the areas where the readings are taken or does one need to to stick to the rigid rules, I applied them myself as a senior meteorologist inspecting similar sites? But was often met with the reply I've tended to come to view as acceptable since becoming an 'amateur' meteorologist. The reason we are graded C3 is for exactly the same reason, to have consistency for the professional forecaster then there must be consistency for the professional observation, correctly sited as per WMO regulations. My max is regularly about 2C below that recorded at Doncaster Airport since I began using Davis equipment. I am equally sure if I reverted back to the standard thermometers, not even in a screen, simply in a sheltered area of the garden then my max values would match those of the airport. It depends what you want whilst bearing in mind grading stations, hence as I've commented the C3 grade. Another station 3 miles from here but not a member of COL reports regularly within about 1C of my values.

I know the limitations but its fun to have ones own record, now over 15 years,to compare with Met O data.

I always make comment in my weather diary, on my web site under Statistics/Excel, when making corrections and am at the moment considering taking down the note about adding 0.5C to the max values, started when I ran comparisons using Met thermometers in my garden with my office at RAF Finningley over a 2 year period 1992-4.

not having spell check is a right pain!

Edited August 13, 2011 by johnholmes

[reef]

I have replied earlier and made comment about the values.

Having got the COL official data for June I show it here for comparison.

Auckley Absolute Max(about 1.5 miles away from me)=32.4C mine was 32.9C both on 27 June.

His avge max was 21.0C mine was 21.4C.

Another observer with similar status to the Auckley one also recorded 21.0C as the mean max. His absolute max obviously has an error as it was reported as 21.7C, perhaps it should have been 31.7C but I have not seen a correction yet.

Thus for June at least my max values seem in line with 2 other stations within 1.5 to 3.5 miles from me!

Other relevant comments from the June COL issue for this or close by areas

Auckley commented it was the highest June value since 1992

Ashover(edge of Peak District)500ft+ height=28.6C highest since 29.5C 19/06/05

Louth=31.8C

Hull-north=31.9C the 3rd highest ever since started in 1989

Collingham-?=32.2C highest since before 1962

Whitby=30.7C the highest ever in its 34 year history.

As I've suggested before my temperature max is, in my view, within 0.5C of previously tested NPL checks, so I think perhaps this area does have a bit of a micro climate of its own in certain synoptic situations that favour high temperatures for this area. It is of course possible that the Davis thermometer sensor has drifted off but a bit unlikely in my view.

I understand your scepticism of my figures though but I do, as a retired professional who once had the task of checking such figures, believe my max temperatures are not as far out as you appear to imply-rest assured they are kept under close scrutiny!

Hi John,

I think its unlikely your Davis thermometer has drifted (mine was actually only 0.1C out on checking with a temperature probe calibrated to 0.01C from work and i check it regularly. I actually think its as simple as the shielding on the standard Davis VP2 not being sufficient on occasion in strong sunshine.

Davis themselves did a comparison and a difference as high as 5.3C was observed compared to a Qualimetrics setup in hot, sunny and still conditions:

http://www.davisnet....ws/ars_vs_c.pdf

Theres obviously microclimates and the limitations of space to take into account aswell, indeed, if anything I record slightly lower maxima and higher minima here on occasion compared to nearby official stations. I wouldnt necessarily look at the absolute maxima as a guide though, when testing an unshielded station side by side I often found the greatest difference to be on cloudy days. This occured because the shielding on the Davis with FARS was completely sufficient but the unshielded station was still being affected even though the sun wasnt out.