1814 was a cold year with a severe winter, a cold spring overall, a cold summer and a cold autumn. Despite the coldness of 1814, it  did produce a surprise month.

Jan: -2.9   (-5.8)
Feb: 1.4   (-2.5)
Mar: 2.9   (-1.7)
Apr: 9.6    (+1.6)
May: 9.2   (-2.3)
Jun: 12.2  (-2.3)
Jul:  16.0  (-0.1)
Aug: 14.7 (-1.1)
Sep: 12.8 (-0.4)
Oct:  8.1  (-1.3)
Nov:  4.7  (-0.6)
Dec: 4.3   (+1.1)

The severe cold spell began on the 27th of December 1813 and the daily CET mean remained below zero until the 28th of January 1814

The period 27th December 1813-27th -January 1814 had a CET average of -3.15C. Not surprisingly, the Thames froze and the last of the great Frost Fairs was held at the start of February. The weather turned somewhat milder during the second week of February but the cold returned during the back end of February and continued well into March. The CET for 1st-19th of March 1814 was just 0.4C.

Snowfalls were often heavy and it was one of the snowiest winters ever recorded

It warmed up during the last third of March but the real surprise was the April. April 1814 was a notably warm month in what was a notably cold year. Mid-month was particularly mild.

The cold returned during May, the 5th and 24th were particularly cold days. May returned a CET that was less than that of April and it is one of only 6 occasions that this happened

January: 3rd coldest on record (1st-25th Jan, CET: -3.6)
April warmer than May

Winter 1813-14: 4th coldest on record, the CET for 21st December 1813- 20th March 1814 is -0.3C 

January-March 1814 is the 3rd coldest such period ever recorded with a CET of 0.47, only 1684 and 1740 had colder first quarters to a year

All 4 seasons are within the top 50 coldest of their groupings

The winter of  1813-14 is the 4th driest on record 

The annual CET for 1814 is 7.75C and it is the 7th coldest year ever recorded

Well we certainly won't see a frost fair on the Thames in London at least until the next ice age.

Drawing of the frost fair of 1814

http://upload.wikimedia.org/wikipedia/en/a/af/Frost_Fair_of_1814_by_Luke_Clenell.jpg

And this from the Museum of London, a piece of shortbread bought at the frost fair of 1814

http://www.bridgeman.co.uk/search/view_image2.asp?image_id=227375

Old London Bridge was demolished in 1831 and the was Thames embanked in parts during the 19th century. This allowed the Thames to flow more freely and less susceptible to freezing.

If London Bridge hadn't been demolished then it is possible there would have been frost fairs during the following winters

1837-38, 1854-55, 1878-79, 1879-80, 1879-80, 1880-81, 1890-91, 1894-95, 1939-40, 1946-47, 1962-63, 1985-86

A very severe winter with a CET of 0.4, winter 1813-14 extended well into March  (27th December 1813 - 19th March 1814 CET: -0.6)

Also contains the longest known spell of subzero CET daily means (27th December 1813 - 27th January 1814 CET: -3.1)

The last of the Great Frost Fairs was held on the Thames in London

Here's an extract from Thomas Brown of Cirencester

"The frost commenced on the 26th December 1813, the thermometer placed against a house in Cirencester and taken at 8.30 am fluctuated between 12F and 22F for the first 3 weeks, during this period there were two falls of snow about 2 inches deep. The sky was clear and there was little wind always from the north or east. At the beginning of the fourth week, there was a great disturbance in the atmosphere, high winds and a fall of 15 inches of snow with deep drifts, stopping all traffic of the roads. Hard frosts followed, the thermometer falling to 10F on the 25th January, the wind then shifted to south and days thawed suceeded by frosty nights followed.
On the 3rd February, two dense concentric circles appeared around the moon and on the 5th we had snow and then a rapid thaw leaving only drifts of snow. The frost then resumed and continued with keen winds to the end of February; a slight tendency to thaw in the beginning of March was followed by a week of steady, clear, frosty weather until the 12th, about which time crystals of snow fell, then a week of cold easterly winds with severe frosts until the 20th March, when a south wind brought mild weather and rain."

Temperatures and wind direction at Tottenham

December

1. 37f, 33f    E
2. 40f, 37f    SE
3. 43f, 40f    SE
4. 44f, 40f    NE
5. 44f, 36f    N
6. 44f, 36f    N
7. 44f, 41f    NE
8. 44f, 40f    NE
9. 44f, 39f    NE
10. 43f, 37f  NE
11. 42f, 37f  NE
12. 37f, 29f  SE
13. 37f, 26f  NW
14. 35f, 25f  NW
15. 38f, 26f  NW
16. 49f, 40f  SW
17. 51f, 50f  S
18. 54f, 44f  SW
19. 50f, 35f  SW
20. 45f, 31f  W
21. 46f, 32f  NE
22. 47f, 36f  SW
23. 47f, 38f  SW
24. 53f, 46f  SW
25. 51f, 41f  SW
26. 41f, 28f  NW
27. 31f, 25f
28. 30f, 24f
29. 30f, 19f
30. 32f, 22f  NW
31. 35f, 22f  N

January

1. 31f, 20f    
2. 32f, 28f
3. 33f, 29f
4. 33f, 25f     E
5. 33f, 32f     NE
6. 34f, 15f     N
7. 28f, 11f     NW
8. 31f, 12f     NW
9. 29f, 8f       NW
10. 26f, 21f   NW
11. 25f, 15f   SE
12. 27f, 15f   N
13. 30f, 14f   NE
14. 26f, 19f   NE
15. 31f, 20f   E
16. 32f, 22f   NE
17. 30f, 11f   N
18. 36f, 30f   E
19. 34f, 28f   NE
20. 33f, 14f   NE
21. 26f, 14f   VAR.
22. 32f, 8f     N
23. 35f, 15f   N
24. 33f, 24f   VAR.
25. 36f, 20f   VAR.
26. 36f, 33f   SW
27. 39f, 33f   W
28. 40f, 28f   VAR.
29. 41f, 32f   VAR.
30. 40f, 25f   W
31. 38f, 26f   NW

February

1. 36f, 26f    NW
2. 41f, 24f    N
3. 33f, 19f    N
4. 32f, 19f    W
5. 38f, 29f    SW
6. 44f, 33f    NW
7. 40f, 32f    W
8. 50f, 35f    SW
9. 47f, 40f    SW
10. 49f, 42f  SW
11. 50f, 35f  S
12. 48f, 39f  S
13. 46f, 37f  SE
14. 41f, 29f  NE
15. 38f, 29f  NE
16. 39f, 28f  NE
17. 33f, 19f  NE
18. 39f, 30f  NE
19. 40f, 23f  NE
20. 31f, 18f  VAR.
21. 34f, 19f  SE
22. 32f, 21f  E
23. 32f, 18f  SE
24. 33f, 18f  E
25, 34f, 21f  SE
26. 35f, 24f  NE
27. 39f, 26f  SE
28. 41f, 30f  SW

March

1. 45f, 31f     VAR.
2. 45f, 31f     SW
3. 42f, 30f     E
4. 35f, 31f     NE
5. 34f, 28f     NE
6. 34f, 28f     NE
7. 32f, 21f     E
8. 33f, 26f     NE
9. 34f, 27f     NE
10. 35f, 29f   NE
11. 41f, 32f   NE
12. 39f, 21f   NE
13. 38f, 30f   N
14. 36f, 30f   NE
15. 37f, 30f   NE
16. 40f, 29f   NE
17. 39f, 28f   NE
18. 37f, 29f   NE
19. 35f, 30f   NE
20. 49f, 35f   SE

 Some daily reports
26th-29th Dec: A succession of thick fogs.
4th Jan: The air has been loaded with particles of freezing water. These attached themselves to all objects, crystallizing in the most regular and beautiful manner. A blade of grass was thus converted into a pretty thick stalagmite.
5th Jan: Snow early and during the day, the wind increasing in force from the NE.
6th Jan: A dark morning. Snow falling in some quantity. Instead of driving loose before the wind, it was collected occasionally into a ball, which rolled on, increasing till its weight stopped it, thousands of these were seen to be lying in the fields, some of which several inches in diameter.
11th Jan: The river Lea is now firmly frozen and the Thames so much encumbered with ice as that navigation is scarcely practicable. The quantity of snow which has fallen in the upper parts of hampshire is very great, lying in many places 15 feet deep.
Jan 13th: From the uncommon depth of the snow, the streets appeared almost deserted (Dublin)
15th Jan: The masses of ice and snow had accumulated in such quantities at London Bridge, on the upper side, yesterday that it was utterly impossible for barges or boats to pass up.
18th Jan: A snowy morning.
19th Jan: A snowy day
23rd Jan: Snow morning and evening.
24th Jan: About 2pm, a squall with plenty of snow.
26th Jan: Snow followed by small rain
27th Jan: A misty thaw.
29th Jan: Stormy, snow early then steady rain then followed by more snow.
31st Jan: Sudden heavy snow shower about 7pm
3rd Feb: All avenues from Cheapside to the different stairs on the banks of the river were distinguished by large chalked boards announcing "a safe footway over the River to Bankside." Several booths, formed of blankets and sail-cloths and ornamented with streamers and various signs were also erected in the very centre of the river., where the visitors could be accomodated with various luxuries. In one of the booths, the entertaining spectacle of a sheep roasting was exhibited.
5th Feb. Crimson sky at sunrise: hollow wind, snow and sleet.
7th Feb:
"Printed to commemorate a remarkably severe frost which commenced December 27, 1813, accompanied by an unusual thick fog, that continued 8 days ad was succeeded by a tremendous fall of snow, which prevented all communication with the Northern and Western raods for several days. The Thames presented a complete field of ice between London and Blackfriars bridges, on Monday the 31st of January 1814."

18th Feb: Much hoar frost, some rain evening.
19th Feb: Hoar frost
20th Feb: Hoar frost
22nd Feb: Hoar frost
1st Mar: Damp and cloudy, hollow wind, sleet pm.
2nd Mar: Rain and sleet at intervals.
3rd-8th Mar: Snow at intervals, the country has become white again with snow.
9th Mar: Snow more plentiful in the night
10-12th Mar: Snow at intervals.
21st Mar: Rainy