1817: A very very odd year

[Weather-history]

Another year from the past but this one is absolutely bizarre, 1817.Months compared to 1781-1810 average

Jan: 4.5 (+1.6)

Feb: 6.4 (+2.5)

Mar: 5.5 (+0.9)

Apr: 7.6 (-0.2)

May: 8.7 (-2.

Jun: 15.1 (+0.6)

Jul: 14.1 (-2.0)

Aug: 13.6 (-2.2)

Sep: 13.2 (0.0)

Oct: 6.4 (-3.0)

Nov: 9.1 (+3.

Dec: 2.5 (-0.7)

The only instance of May being colder than November

The second half of May 1817 was nearly a degree colder than the first half of November 1817

May and October 1817 are the third and second coldest months respectively ever recorded for each of those months .

November 1817 was the the 3rd warmest November ever recorded at the time

The first half of October 1817 was 1.5C colder than the second half of November 1817

The leap in CET between October and November 1817 is the largest ever record (+2.7)

The leap between May and June 1817 is the largest ever recorded (+6.4)

April 1817 was exceptionally dry, the driest on record until April 1938 but May was very wet.

Autumn 1817 was until 1978 the driest autumn on record, whilst the summer is 8th wettest on record.

All in all, a year with great variety. There are few years as ridiculous as 1817.

Edited October 25, 2006 by Mr_Data

[Osbourne One-Nil]

Peter Tattum told me once that he has great memories of 1817 for those very reasons.

[Weather-history]

Peter Tattum told me once that he has great memories of 1817 for those very reasons.

:blink: Cheeky

[MP-R]

An interesting read Mr Data. How often do you think October is warmer than May? Wasn't that the case in 2005?

[Weather-history]

An interesting read Mr Data. How often do you think October is warmer than May? Wasn't that the case in 2005?

Yes it happened in 2005. Its about a 1 in 7 year occurrence.

One thing I forgot to mention is that February had the same CET as October. February has never been warmer than October but the closest it came was in 1817

February as warm as October

May colder than November

May, 6.4C colder than June

October, 2.7C colder than November

April was the driest on record at the time (now 2nd driest)

Summer was the 3rd wettest on record (now 8th wettest)

Autumn was the driest on record (now 2nd driest)

An absolutely bizarre year

[ukmoose]

Any volcanic eruptions around that year? Certainly very odd but really interesting Mr D.

Moose

[Weather-history]

Any volcanic eruptions around that year? Certainly very odd but really interesting Mr D.

Moose

Well it came a year after the "year without a summer", 1816. Tambora erupted in 1815, so maybe an after effect was still being felt from that.

[Summer of 95]

An interesting read Mr Data. How often do you think October is warmer than May? Wasn't that the case in 2005?

1996 and 2001 as well, 1994 and 1995 must have been close too?

Has November ever been warmer than May (1994 can't have been much cooler) or October warmer than June?

[Nick H]

Looking at the wild swings in monthly temperatures in 1817, how much confidence do we actually have in the recording equipment of 200 years ago? Do these figures seem plausible? Is the series of such repute that we have to take this data as read? The autumn temps in particular look extraordinary.

Edited October 26, 2006 by Nick H

[drgl]

something i've often wondered too.............

[Weather-history]

Has November ever been warmer than May ?

Er... thats just another way of saying "has May ever been cooler than November?" which I have answered.

There has never been an October warmer than June

Edited October 26, 2006 by Mr_Data

[Summer of 95]

Er... thats just another way of saying "has May ever been cooler than November?" which I have answered. :lol:

There has never been an October warmer than June

:lol:

[Thundery wintry showers]

October was definitely warmer than May in 1995 (May 11.6, October 12.9)

In 1994 it wasn't, although it was a very close run thing. October 1994 had a very fine second week, but the start featured an exceptionally cold northerly, and the final third was rather cool, so the mean temperature was a little below average.

[Weather-history]

Looking at the wild swings in monthly temperatures in 1817, how much confidence do we actually have in the recording equipment of 200 years ago? Do these figures seem plausible? Is the series of such repute that we have to take this data as read? The autumn temps in particular look extraordinary.

The fact that it happened in that year and not really to any degree in previous years , I think we can have some confidence in the figures. If most years were showing wide fluctations back then, then I would question it but its statistically plausible.

[Weather-history]

A graph showing the CET values plotted through the year. The blue horiontal lines are the 30 year average (1781-1810) for each month. You can see the remarkable difference between October and November.

[Somerset Squall]

Thanks for the info Mr_D. Really interesting stats, a very messed up year indeed, and with unusual variety!