January 2013 statistics and summaries

[TonyH]

Llanwnnen, Ceredigion, Wales

Slightly cold overall; snowy spell 18^th – 25^th; rainfall near average

Mild early and late with a cold, snowy spell between. No extreme temperatures. Much of the rain fell in the final week.

1^st – 8^th: Mild and quite dry but cloudy. The start of the year saw benign, quiet mild weather after all the rain and wind of December! Atmospheric pressure reached 1038mbar its highest level since last May. There was some drizzle at times,.

9^th - 14^th : Rather cold and unsettled, rain or showers at times. Dry, sunny intervals between, and with some clear, frosty nights, down to -4.7c 13^th.

15^th - 25^th: Cold to very cold, mainly cloudy, sleet or snow at times. Not your classic bitter Winter cold spell, temperatures never got below -3c with the persistent cloud cover, however it was quite snowy. Heavy sleet turned to snow on the 18^th giving a 9cm covering, while higher up in the nearby Carmarthenshire hills level snow was hard to estimate due to drifting, but was at least 15cm deep. The snow cover then lay for over one week as temperatures remained low throughout, never getting much above +3c, and with just a gradual thaw. There was only a little further snow after 18^th at Lampeter, unlike some parts of SW Wales which were hit badly again 23^rd. The sun came out at long last on the 24^th after 8 successive generally overcast days! The thaw arrived with heavy rain and strong winds the following day.

26^th – 31^st: Mild to very mild, very unsettled and windy. Periods of rain and showers, heavy at times. Thunderstorms with vivid fork lightning evening of 26^th. Temperatures peaked at 11.4c 29^th,

Total rainfall: 119.9mm

Wettest day: 20.2mm 26^th

Rain days >0.2mm: 23

Wet days >1.0mm: 17

Days of heavy rain >10mm: 5

Mean temperature: 4.0c

Mean Max: 6.3c

Mean Min: 1.7c

High Max: 11.4c 29^th

Low Max: 0.6c 18^th

High Min: 8.9c 8^th

Low Min: -4.7c 13^th

Air frost: 16

Ground frost: 18

Ice day (max below 0c): 0

Mean RH: 90% approx

High RH: 100% various dates

Low RH: 67% 24^th

Predominant wind directions: SSE

Mean wind speed: 2.0mph

Mean pressure: 1012mbar

Max pressure: 1038mbar 4th

Min pressure: 988mbar 27th

Days with:

Hail: 2

Gale: 1

Thunder: 1

Lightning only: 1

Snow or sleet: 11

Snow lying 0900:8

Fog: 2

Fog at 0900: 1

[SP1986]

January 2013 Statistics

This was a month characterised by big differences in the weather and changes throughout the month. At the start of the month, it was fairly mild, with temperatures largely in double figures in the daytime, and retaining the above average theme at night. Towards mid-month however a change took place whereby much colder air came in, via the continent. The temperatures reverted to low single figures and minus figures by night. Due to the amount of cloud, the temperature didn't get particularly low, only falling to -2.5C mid month. No ice days occurred, however mid month again, the temperature fell down to 0.8C. There was also a fair bit of snow mid-month with 4 days snowfall occurring, which was above the seasonal expectation, and well above January expectation. The snow hung on for a few days but finally melted towards the end of January. Then the milder weather took over once again with double figure temperatures, culminating in 14.1C on the 29th January, the highest of the month, and in line with expectations.

Overall.. a cool month considering, locally below average, but with temperature deviations about where we would expect them in January.

Below are the statistics for my weather station during the month of January

Mean Maximum: 6.4C

Mean Minimum: 2.1C

Overall Mean: 4.25C

Monthly Rainfall total: 63.9mm

Rainfall days: 15

Max rainfall in one day: 16.2mm (26th January)

Total Snowfall: 8.5cm

Snowfall Days: 4

Max snowfall in one day: 4.5cm (26th January)

Highest daily maximum temperature: 14.1C (29th January)

Lowest daily maximum temperature: 0.8C (16th January)

Highest daily minimum temperature: 10.5C (3rd January)

Lowest daily minimum temperature: -2.5C (16th January)

Days with Ground Frost: 18

Days with Air Frost: 13

Days of falling snow: 4

Days of lying snow: 5

Thunder days: 0

Temperature frequency breakdown

Maximum temperature:

0.0C to 4.9C: 14 days

5.0C to 9.9C: 6 days

10.0C to 14.9C: 11 days

Minimum temperature:

-5.0C to -0.1C: 13 days

0.0C to 4.9C: 8 days

5.0C to 9.9C: 9 days

10.0C to 14.9C: 1 day

Compared to the December CET (81-10 average = 4.4), my average comes in at 0.2C below the CET average, making it a sligtly below average month when compared to the Central England mean

[TonyH]

Compared to the December CET (81-10 average = 4.4), my average comes in at 0.2C below the CET average, making it a sligtly below average month when compared to the Central England mean

[Aaron]

Mean: 2.8°C

Mean maximum: 4.7°C

Mean minimum: 0.9°C

Maximum temperature: 13.0°C (day 29)

Minimum temperature: -7.1°C (day 16)

Lowest maximum: -3.7°C (day 16)

Highest minimum: 9.4°C (day 3)

Days >10°C: 4

Days <5°C: 17

Days <0°C: 3

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Precipitation: 38.9 mm

Rain days >1 mm: 6

Rain days >0.1 mm: 14

Most in one day: 20.5 mm* (day 26)

Maximum snow depth: 25 cm (day 26)

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Maximum pressure: 1035.8 mb (day 4)

Minimum pressure: 983.3 mb (day 27)

Maximum wind gust: 60.1 mph (day 31)

Sunshine: 38.4 hours

Mean: 1.2 hours

Most in one day: 6.2 hours (day 9)

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Thunder: 1

Lightning: 2

Hail: 0

Snow falling: 9

Snow on ground: 14**

Air frost: 16

*entirely snow melt

** excludes 2 or 3 days with patchy cover

[johnholmes]

I was away 20-31 January so the only totally reliable data are the temperatures.

Mean=4.3(3.5)

Avge Max=6.1(5.9)

Avge Min=2.4(1.2)

They hardly show what a variable month temperature wise it has been though

The first 8 days the Mean=8.8C

The next 17 days=0.9C and the final 6 days=7.6C

Snow cover(more than half cover) at 0900=8 days estimate with snow falling on at least 8 days

[Styx]

HOBART ( pop 200,000 ) is Tasmania's capital city, situated at sealevel, at the base of Mt. Wellington ( 1270m/4200ft ).

January - Mid summer

Superheated air over inland Australia came forth at the beginning of the month on a strong northerly airstream, bringing Hobart its highest temperature that has ever been recorded, and precipitating the most destructive bushfires Tasmania has seen since 'Black Tuesday', 1967. Follow-up days were warm - sunshine weakened by extensive smoke haze - before a progressively cooler temperature trend developed as winds of a more regional nature became established.

The synoptic theme emulated the last 3 and a half months with a belt of high pressure systems with their central ridging chiefly at Tasmanian latitudes, weakening cold fronts on their approach to Tasmania.

This resulted in this being the 4th month in a row with a rainfall deficet of more than 50% - with this month being the driest of the four.

It was the 15th consecutive month with an average temperature that exceeded the 1981-2010 average.

Average maximum: 23.9 ( +1.7 )

Average minimum: 13.1 ( +0.5 )

Rainfall: 11mm ( Average 47mm )

Extremes in daily temperature for January ( Records since 1882 ):

Highest maximum: 41.8 ( Previous record 40.8 in 1976 )

Lowest maximum: 18.1 ( Record 11.1 in 1885 )

Highest minimum: 23.4 ( Previous record 22.9 in 1887 )

Lowest minimum: 8.9 ( Previous record 3.3 in 1902 )

[reef]

Hedon, East Yorkshire.

January 2013

Warmest Max: 13.1°C (on 29/01/13)

Coldest Max: -0.1°C (on 16/01/13) - Coldest Since 1992

Warmest Min: 9.5°C (on 03/01/13) - Mildest Since 2005

Coldest Min: -8.3°C (on 17/01/13) - Coldest Since 1982

Average Max: 6.1°C (-0.6°C Below 1981-2010 Average)

Average Min: 2.4°C (Equal to 1981-2010 Average)

Overall Average: 4.2°C (-0.3°C Below 1981-2010 Average)

Rain: 48.8mm (87% Of Normal)

Wettest Day: 26th (10.6mm)

Sunshine: 59 hours (104% Of Normal)

Air Frosts: 6

Sleet/Snow Falling: 13 days

Snow lying at 0900: 13 days

Dry Days: 5

Wet Days: 26

Days With Rain >1.0mm: 12

Days With Rain >10mm: 1

Thunder Days: 1

Days With Fog: 2

The snowiest January since at least 1987. It was a month of close to average temperatures, sunshine and rainfall, but with quite severe extremes. The month contained a two week cold spell bookended by very mild weather.

The first 10 days were exceptionally mild, dull and rather dry as high pressure to the south dominated. Between the 3rd and 9th the temperature stayed above 5.7°C as persistent cloud associated with the mild air sourced from the south-west kept night-time minima high. It then turned rather cold in the second week with the first snowfall arriving on the 14th giving a level depth of 10cm. Under clear skies the following nights saw extremely low temperatures. The minimum on the 16th of -6.7°C was the lowest since 1987, but was beaten immediately the following night with a low of -8.3°C, the coldest since 1982. A further heavy snowfall deposited another 5cm on the 18th and was accompanied by thunder for the first time in January since 2004. A slow thaw then occured over the following 7 days as easterly winds brought persistent cloud, temperatures in the 0-3°C range and no sunshine at all. The breakdown on the 26th saw snowfall almost the entire night, but due to a 2 hour spell of sleet managed only a 5cm slushy cover which melted completely the following day under sunshine and later, heavy rain.

Just like the start of the month, the final 5 days were mild and windy but with long dry periods. Fortunately cloud levels were somewhat lower, boosting the sunshine total for the month to just above the average and hiding the exceptionally dull period during the previous 7 days in the final total.

[Stargazer]

My statistics for central Reading in January 2013:

Average maximum: 6.5

Average minimum: 2.8

Average for month: 4.6

Highest maximum: 13.5 (January 29)

Lowest maximum: 0.1 (16)

Highest minimum: 9.7 (29)

Lowest minimum: -4.3 (22)

Air frosts: 8 (although we had three nights with a minimum of exactly 0.0 too)

Ice days: 0

Days of falling snow: 5

Days of lying snow: 5

Rainfall: no data available for this site; Reading University shows around 45mm for the month, which is slightly drier than average.

Statistically an unexceptional month overall, with daytime maxima colder than average and night time minima slightly above average, but the reality is more interesting. A dull and mild first week, followed by a dull and cold second week. There was a little wet snow on the 14th that rapidly turned to sleet, then on the 18th the area had its heaviest snowfall since January 2010 (11cm). It remained very cold and generally dull until the 25th, after which the month ended on a mild note, with the temperature reaching 13.5 on the 29th. The last week was also reasonably sunny, largely making up for the exceptionally dull start to the month.