November 1821 to March 1822 was very mild

CETs (anomalies compared to the 1971-2000 average) (C)

November: 8.6 (+1.7)
December: 6.4 (+1.3)
January: 4.7 (+0.5)
February: 6.3 (+2.1)
March: 7.8 (+1.5)

Number of days recording these temperatures in London
60F+: 10 (6.6%)
50F-59F: 79 (52%)
Minima
32F and below: 37 (24.5%)

Lowest minimum was on the 28th February 1822 with 22F

The wind blew from the SW on 55 days in that period (36%)
The wind blew from the E only on 5 days (3%)

The warm spell actually began in September 1821 and lasted until June 1822 that period having a CET that was about 1.3C above the 1971-2000 average.

September 1821: 14.9 (+1.2)
October 1821: 10.4 (+0.2)
April 1822: 8.3 (+0.2)
May 1822: 12.7 (+2.3)
June 1822: 17.1 (+3.0)

---