Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Chelsea. The lines show the 2026 daily maximum and minimum. 0 days in 2026 matched or passed a record. Temperatures are in degrees Celsius.
Daily record high and record low at Chelsea, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
11.1 C (52.0 F)
-40.0 C (-40.0 F)
n/a
n/a
Feb
11.1 C (52.0 F)
-37.2 C (-35.0 F)
n/a
n/a
Mar
25.6 C (78.1 F)
-37.2 C (-35.0 F)
n/a
n/a
Apr
30.6 C (87.1 F)
-18.9 C (-2.0 F)
n/a
n/a
May
33.3 C (91.9 F)
-6.1 C (21.0 F)
n/a
n/a
Jun
35.0 C (95.0 F)
-0.6 C (30.9 F)
n/a
n/a
Jul
36.1 C (97.0 F)
6.1 C (43.0 F)
n/a
n/a
Aug
37.2 C (99.0 F)
3.9 C (39.0 F)
n/a
n/a
Sep
33.9 C (93.0 F)
-1.7 C (28.9 F)
n/a
n/a
Oct
28.3 C (82.9 F)
-7.8 C (18.0 F)
n/a
n/a
Nov
22.2 C (72.0 F)
-20.6 C (-5.1 F)
n/a
n/a
Dec
14.0 C (57.2 F)
-41.1 C (-42.0 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Chelsea still stand. 1933 holds the most, with 57.
Standing records at Chelsea by the year they were set
Year set
Standing records
1927
10
1928
24
1929
22
1930
23
1931
30
1932
27
1933
57
1934
56
1935
27
1936
43
1937
21
1938
28
1939
23
1940
31
1941
22
1942
28
1943
31
1944
22
1945
38
1946
26
1947
43
1948
23
1949
29
1950
25
1951
19
1952
10
1953
29
1954
25
1955
25
1956
26
1957
30
1958
20
1959
26
1960
10
1961
16
1962
21
1963
27
1964
23
1965
26
1966
20
1967
13
1968
26
1969
17
1970
24
1971
18
1972
17
1973
20
1974
22
1975
25
1976
38
1977
27
1978
15
1979
36
1980
17
1981
35
1982
24
1983
28
All-Time Record Progression
1 new records
1 all-time records were set at Chelsea between 1 August 1975 and 1 August 1975. Each dot is a new record.
When Chelsea set new all-time records
Date
Kind
Detail
1975-08-01
Record high maximum temperature
Record high maximum temperature 37.2 C (99.0 F)
Wettest Day of Each Month
Oct: 90.7 mm (3.6 in)
The wettest day on record for each calendar month at Chelsea. The most was 90.7 mm (3.6 in) on 12 October 1946.
Record daily precipitation for each month at Chelsea
Month
Record daily precipitation (mm)
Date
Jan
47.0 mm (1.9 in)
8 January 1978
Feb
33.5 mm (1.3 in)
2 February 1973
Mar
45.9 mm (1.8 in)
21 March 1980
Apr
39.9 mm (1.6 in)
29 April 1962
May
54.4 mm (2.1 in)
25 May 1943
Jun
66.0 mm (2.6 in)
7 June 1971
Jul
86.4 mm (3.4 in)
29 July 1939
Aug
64.8 mm (2.6 in)
22 August 1972
Sep
73.7 mm (2.9 in)
20 September 1957
Oct
90.7 mm (3.6 in)
12 October 1946
Nov
34.8 mm (1.4 in)
26 November 1979
Dec
45.7 mm (1.8 in)
16 December 1974
Period of Record Coverage
1927 to 1983
Complete yearUnder 90 percent of days
57 years of record at Chelsea, 1927 to 1983. 3 years have data for under 90 percent of days and are left out of rankings: 1927, 1937, 1946.
Cooler than the station meanWarmer than the station mean
One stripe for each of 53 complete years at Chelsea, 1928 to 1983. Blue stripes are years cooler than the station's own mean of 5.2 C (41.4 F); red stripes are warmer. The coolest year was 1934, at 3.7 C (38.6 F), and the warmest was 1953, at 6.8 C (44.3 F). The strongest colour marks a difference of 1.6 C (2.9 F).
Annual mean temperature at Chelsea as warming stripes, 1928 to 1983
Year
Annual mean temperature
Difference from the station mean
1928
6.4 C
+1.16 C
1929
5.4 C
+0.18 C
1930
5.6 C
+0.39 C
1931
6.5 C
+1.31 C
1932
5.3 C
+0.07 C
1933
4.7 C
-0.50 C
1934
3.7 C
-1.56 C
1935
4.1 C
-1.10 C
1936
4.1 C
-1.15 C
1938
5.4 C
+0.22 C
1939
4.3 C
-0.91 C
1940
4.2 C
-1.04 C
1941
5.5 C
+0.25 C
1942
5.5 C
+0.31 C
1943
3.9 C
-1.29 C
1944
5.2 C
-0.02 C
1945
5.2 C
-0.06 C
1947
5.0 C
-0.21 C
1948
5.3 C
+0.04 C
1949
6.3 C
+1.10 C
1950
4.6 C
-0.60 C
1951
5.2 C
-0.02 C
1952
6.0 C
+0.78 C
1953
6.8 C
+1.59 C
1954
4.8 C
-0.42 C
1955
5.5 C
+0.25 C
1956
4.2 C
-1.07 C
1957
5.2 C
-0.04 C
1958
4.3 C
-0.90 C
1959
4.8 C
-0.39 C
1960
5.4 C
+0.13 C
1961
5.2 C
-0.01 C
1962
4.3 C
-0.91 C
1963
4.3 C
-0.95 C
1964
5.8 C
+0.61 C
1965
5.0 C
-0.25 C
1966
5.7 C
+0.46 C
1967
5.0 C
-0.18 C
1968
5.4 C
+0.20 C
1969
5.8 C
+0.57 C
1970
5.2 C
-0.04 C
1971
5.3 C
+0.07 C
1972
4.4 C
-0.86 C
1973
6.5 C
+1.28 C
1974
5.0 C
-0.26 C
1975
6.0 C
+0.77 C
1977
5.9 C
+0.64 C
1978
5.1 C
-0.17 C
1979
5.9 C
+0.63 C
1980
5.0 C
-0.26 C
1981
6.2 C
+0.94 C
1982
5.4 C
+0.19 C
1983
6.1 C
+0.83 C
The fitted trend in annual mean temperature here over 1928 to 1983 is 0.09 C (-0.03 to 0.22) per decade. The interval includes zero, so the trend is not clearly different from zero. In Fahrenheit: 0.2 F (-0.1 to 0.4) per decade. The slope is a straight line fitted to 53 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Chelsea
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.09 C (-0.03 to 0.22) per decade
0.2 F (-0.1 to 0.4) per decade
1928 to 1983
53
Not clearly different from zero
Mean daily maximum
0.00 C (-0.12 to 0.11) per decade
-0.01 F (-0.22 to 0.20) per decade
1928 to 1983
53
Not clearly different from zero
Mean daily minimum
0.19 C (0.03 to 0.34) per decade
0.3 F (0.1 to 0.6) per decade
1928 to 1983
53
Rise
A year is complete when all 12 months have at least 20 days of both daily maximum and daily minimum readings. The annual mean is the mean of the monthly means. The trend describes this one station over this period; it does not say what caused the change.
Extremes by Year
1927 to 1983
Yearly extremes at Chelsea: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
37.2 C (99.0 F)
1975
33.3 C (91.9 F)
57
Coldest night (TNn)
-41.1 C (-42.0 F)
1933
-32.8 C (-27.0 F)
57
Wettest day (Rx1day)
90.7 mm (3.6 in)
1946
39.9 mm (1.6 in)
57
Wettest five days (Rx5day)
110.0 mm (4.3 in)
1957
64.8 mm (2.6 in)
57
Longest dry spell (CDD)
36 days
1961
15 days
57
Hottest day (TXx)
The hottest day of the year at Chelsea, 1927 to 1983. The record is 37.2 C (99.0 F) in 1975, marked on the chart; the median year is 33.3 C (91.9 F).
Hottest day (TXx) at Chelsea by year
Year
Hottest day (TXx)
1927
25.6 C (78.1 F)
1928
32.8 C (91.0 F)
1929
33.9 C (93.0 F)
1930
31.1 C (88.0 F)
1931
36.1 C (97.0 F)
1932
31.7 C (89.1 F)
1933
33.3 C (91.9 F)
1934
34.4 C (93.9 F)
1935
32.2 C (90.0 F)
1936
32.2 C (90.0 F)
1937
33.9 C (93.0 F)
1938
34.4 C (93.9 F)
1939
33.3 C (91.9 F)
1940
32.2 C (90.0 F)
1941
35.0 C (95.0 F)
1942
33.3 C (91.9 F)
1943
31.1 C (88.0 F)
1944
36.1 C (97.0 F)
1945
32.2 C (90.0 F)
1946
33.3 C (91.9 F)
1947
34.4 C (93.9 F)
1948
34.4 C (93.9 F)
1949
36.1 C (97.0 F)
1950
31.1 C (88.0 F)
1951
30.6 C (87.1 F)
1952
33.3 C (91.9 F)
1953
36.1 C (97.0 F)
1954
31.1 C (88.0 F)
1955
36.1 C (97.0 F)
1956
33.9 C (93.0 F)
1957
32.8 C (91.0 F)
1958
30.6 C (87.1 F)
1959
33.3 C (91.9 F)
1960
30.6 C (87.1 F)
1961
31.1 C (88.0 F)
1962
32.8 C (91.0 F)
1963
34.4 C (93.9 F)
1964
34.4 C (93.9 F)
1965
32.2 C (90.0 F)
1966
33.9 C (93.0 F)
1967
30.6 C (87.1 F)
1968
33.3 C (91.9 F)
1969
33.3 C (91.9 F)
1970
33.3 C (91.9 F)
1971
32.8 C (91.0 F)
1972
30.6 C (87.1 F)
1973
33.3 C (91.9 F)
1974
32.2 C (90.0 F)
1975
37.2 C (99.0 F)
1976
32.2 C (90.0 F)
1977
34.4 C (93.9 F)
1978
33.3 C (91.9 F)
1979
33.3 C (91.9 F)
1980
32.2 C (90.0 F)
1981
33.0 C (91.4 F)
1982
34.0 C (93.2 F)
1983
33.0 C (91.4 F)
Coldest night (TNn)
The coldest night of the year at Chelsea, 1927 to 1983. The record is -41.1 C (-42.0 F) in 1933, marked on the chart; the median year is -32.8 C (-27.0 F).
Coldest night (TNn) at Chelsea by year
Year
Coldest night (TNn)
1927
-18.9 C (-2.0 F)
1928
-29.4 C (-20.9 F)
1929
-29.4 C (-20.9 F)
1930
-32.2 C (-26.0 F)
1931
-30.6 C (-23.1 F)
1932
-30.0 C (-22.0 F)
1933
-41.1 C (-42.0 F)
1934
-37.2 C (-35.0 F)
1935
-33.3 C (-27.9 F)
1936
-31.7 C (-25.1 F)
1937
-27.8 C (-18.0 F)
1938
-37.2 C (-35.0 F)
1939
-33.9 C (-29.0 F)
1940
-28.9 C (-20.0 F)
1941
-31.1 C (-24.0 F)
1942
-33.3 C (-27.9 F)
1943
-35.6 C (-32.1 F)
1944
-31.7 C (-25.1 F)
1945
-33.3 C (-27.9 F)
1946
-31.1 C (-24.0 F)
1947
-32.2 C (-26.0 F)
1948
-35.6 C (-32.1 F)
1949
-28.3 C (-18.9 F)
1950
-32.2 C (-26.0 F)
1951
-36.7 C (-34.1 F)
1952
-34.4 C (-29.9 F)
1953
-28.3 C (-18.9 F)
1954
-33.3 C (-27.9 F)
1955
-33.9 C (-29.0 F)
1956
-28.9 C (-20.0 F)
1957
-40.0 C (-40.0 F)
1958
-32.8 C (-27.0 F)
1959
-34.4 C (-29.9 F)
1960
-30.0 C (-22.0 F)
1961
-30.0 C (-22.0 F)
1962
-36.1 C (-33.0 F)
1963
-35.0 C (-31.0 F)
1964
-30.0 C (-22.0 F)
1965
-32.2 C (-26.0 F)
1966
-33.9 C (-29.0 F)
1967
-35.6 C (-32.1 F)
1968
-33.3 C (-27.9 F)
1969
-30.6 C (-23.1 F)
1970
-34.4 C (-29.9 F)
1971
-35.0 C (-31.0 F)
1972
-36.1 C (-33.0 F)
1973
-32.2 C (-26.0 F)
1974
-30.0 C (-22.0 F)
1975
-30.0 C (-22.0 F)
1976
-36.1 C (-33.0 F)
1977
-32.8 C (-27.0 F)
1978
-28.3 C (-18.9 F)
1979
-31.7 C (-25.1 F)
1980
-34.0 C (-29.2 F)
1981
-37.0 C (-34.6 F)
1982
-35.5 C (-31.9 F)
1983
-29.0 C (-20.2 F)
Wettest day (Rx1day)
The wettest day of the year at Chelsea, 1927 to 1983. The record is 90.7 mm (3.6 in) in 1946, marked on the chart; the median year is 39.9 mm (1.6 in).
Wettest day (Rx1day) at Chelsea by year
Year
Wettest day (Rx1day)
1927
30.7 mm (1.2 in)
1928
47.2 mm (1.9 in)
1929
29.5 mm (1.2 in)
1930
28.2 mm (1.1 in)
1931
32.8 mm (1.3 in)
1932
45.0 mm (1.8 in)
1933
42.4 mm (1.7 in)
1934
36.8 mm (1.4 in)
1935
44.5 mm (1.8 in)
1936
33.0 mm (1.3 in)
1937
46.0 mm (1.8 in)
1938
27.9 mm (1.1 in)
1939
86.4 mm (3.4 in)
1940
38.4 mm (1.5 in)
1941
40.1 mm (1.6 in)
1942
63.5 mm (2.5 in)
1943
54.4 mm (2.1 in)
1944
24.6 mm (1.0 in)
1945
39.6 mm (1.6 in)
1946
90.7 mm (3.6 in)
1947
45.7 mm (1.8 in)
1948
40.6 mm (1.6 in)
1949
35.8 mm (1.4 in)
1950
49.5 mm (1.9 in)
1951
31.8 mm (1.3 in)
1952
52.3 mm (2.1 in)
1953
34.3 mm (1.4 in)
1954
33.3 mm (1.3 in)
1955
36.6 mm (1.4 in)
1956
38.1 mm (1.5 in)
1957
73.7 mm (2.9 in)
1958
54.6 mm (2.1 in)
1959
69.9 mm (2.8 in)
1960
24.6 mm (1.0 in)
1961
38.4 mm (1.5 in)
1962
39.9 mm (1.6 in)
1963
35.8 mm (1.4 in)
1964
29.5 mm (1.2 in)
1965
64.3 mm (2.5 in)
1966
34.8 mm (1.4 in)
1967
38.4 mm (1.5 in)
1968
41.4 mm (1.6 in)
1969
45.5 mm (1.8 in)
1970
35.1 mm (1.4 in)
1971
66.0 mm (2.6 in)
1972
64.8 mm (2.6 in)
1973
39.9 mm (1.6 in)
1974
45.7 mm (1.8 in)
1975
39.6 mm (1.6 in)
1976
36.1 mm (1.4 in)
1977
41.4 mm (1.6 in)
1978
47.0 mm (1.9 in)
1979
67.3 mm (2.6 in)
1980
46.4 mm (1.8 in)
1981
27.4 mm (1.1 in)
1982
35.6 mm (1.4 in)
1983
31.1 mm (1.2 in)
Wettest five days (Rx5day)
The wettest five days of the year at Chelsea, 1927 to 1983. The record is 110.0 mm (4.3 in) in 1957, marked on the chart; the median year is 64.8 mm (2.6 in).
Wettest five days (Rx5day) at Chelsea by year
Year
Wettest five days (Rx5day)
1927
61.8 mm (2.4 in)
1928
75.9 mm (3.0 in)
1929
42.4 mm (1.7 in)
1930
63.7 mm (2.5 in)
1931
43.2 mm (1.7 in)
1932
63.5 mm (2.5 in)
1933
75.2 mm (3.0 in)
1934
56.1 mm (2.2 in)
1935
65.8 mm (2.6 in)
1936
54.2 mm (2.1 in)
1937
64.8 mm (2.6 in)
1938
56.4 mm (2.2 in)
1939
101.8 mm (4.0 in)
1940
63.3 mm (2.5 in)
1941
68.6 mm (2.7 in)
1942
75.9 mm (3.0 in)
1943
67.9 mm (2.7 in)
1944
43.9 mm (1.7 in)
1945
62.8 mm (2.5 in)
1946
92.2 mm (3.6 in)
1947
68.8 mm (2.7 in)
1948
80.8 mm (3.2 in)
1949
76.5 mm (3.0 in)
1950
71.8 mm (2.8 in)
1951
52.2 mm (2.1 in)
1952
65.0 mm (2.6 in)
1953
67.3 mm (2.6 in)
1954
55.1 mm (2.2 in)
1955
52.4 mm (2.1 in)
1956
58.8 mm (2.3 in)
1957
110.0 mm (4.3 in)
1958
79.8 mm (3.1 in)
1959
74.0 mm (2.9 in)
1960
64.8 mm (2.6 in)
1961
49.7 mm (2.0 in)
1962
62.5 mm (2.5 in)
1963
57.3 mm (2.3 in)
1964
54.4 mm (2.1 in)
1965
94.1 mm (3.7 in)
1966
61.4 mm (2.4 in)
1967
75.5 mm (3.0 in)
1968
66.8 mm (2.6 in)
1969
89.2 mm (3.5 in)
1970
50.3 mm (2.0 in)
1971
66.0 mm (2.6 in)
1972
82.1 mm (3.2 in)
1973
57.3 mm (2.3 in)
1974
73.5 mm (2.9 in)
1975
54.6 mm (2.1 in)
1976
83.5 mm (3.3 in)
1977
76.5 mm (3.0 in)
1978
62.4 mm (2.5 in)
1979
86.6 mm (3.4 in)
1980
62.8 mm (2.5 in)
1981
55.4 mm (2.2 in)
1982
52.7 mm (2.1 in)
1983
68.3 mm (2.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Chelsea, 1927 to 1983. The record is 36 days in 1961, marked on the chart; the median year is 15 days.
Longest dry spell (CDD) at Chelsea by year
Year
Longest dry spell (CDD)
1927
12 days
1928
14 days
1929
17 days
1930
18 days
1931
15 days
1932
18 days
1933
14 days
1934
19 days
1935
16 days
1936
16 days
1937
14 days
1938
13 days
1939
21 days
1940
12 days
1941
32 days
1942
15 days
1943
13 days
1944
16 days
1945
16 days
1946
12 days
1947
16 days
1948
19 days
1949
13 days
1950
20 days
1951
14 days
1952
17 days
1953
15 days
1954
16 days
1955
16 days
1956
15 days
1957
16 days
1958
20 days
1959
14 days
1960
19 days
1961
36 days
1962
18 days
1963
14 days
1964
15 days
1965
18 days
1966
11 days
1967
18 days
1968
12 days
1969
12 days
1970
14 days
1971
12 days
1972
11 days
1973
11 days
1974
13 days
1975
15 days
1976
12 days
1977
14 days
1978
17 days
1979
14 days
1980
14 days
1981
12 days
1982
17 days
1983
11 days
Each chart shows one value per year; the dot marks the record year. TXx is the hottest daily maximum, TNn the coldest daily minimum, Rx1day and Rx5day the largest one-day and five-day rain totals, and CDD the longest run of days with less than 1 mm of rain. A year with missing days can understate an extreme.
Frost Dates and Growing Season
53 years with a frost
Across 53 years with a frost, the median last spring frost at Chelsea falls on 7 May and the median first autumn frost on 9 October, which leaves a median of 154 days between them.
Fitted over all years, the growing season changes by -1.0 days per decade at this station.
Frost dates and growing season at Chelsea
Measure
Median, all years
Earliest period
Recent period (1953 to 1983)
Recent against earliest
Fitted trend
Last spring frost
7 May
n/a
8 May
n/a
+1.5 days per decade
First autumn frost
9 October
n/a
8 October
n/a
+0.5 days per decade
Growing days
154 days
n/a
152 days
n/a
-1.0 days per decade
A frost day is a day with a daily minimum at or below 0 C (32 F). The last spring frost and the first autumn frost are the last and first such days of the cold season, and growing days are the days between them. A negative trend for the last spring frost means it comes earlier.
Rainfall Return Levels
55 years, 1928 to 1983
A day with at least 40.1 mm (1.6 in) of rain is expected about once in 2 years. A day with at least 92.0 mm (3.6 in) of rain is expected about once in 100 years.
Rainfall return levels at Chelsea: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
40.1 mm (1.6 in)
5 years
51.5 mm (2.0 in)
10 years
60.0 mm (2.4 in)
25 years
71.9 mm (2.8 in)
50 years
81.6 mm (3.2 in)
100 years
92.0 mm (3.6 in)
Longer than the 55 years of record
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 55 years of values from 1928 to 1983.
A return level is an estimate. It is least reliable for the long periods, 50 and 100 years, and for any period longer than the record behind the fit, where the fit has to reach past the largest day actually observed. It is not a forecast.
The largest wettest-day totals in the fit: 86.4 mm (3.4 in) in 1939; 73.7 mm (2.9 in) in 1957; 69.9 mm (2.8 in) in 1959.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Chelsea, at 1964. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1964 ran 0.2 C (0.4 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Chelsea, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1964
+0.2
+0.4
likely
5
Possible change at the station (a move, a new instrument or a new site); the record is kept as measured. A "likely" change has a larger test statistic than a "possible" one. Neither says why the station differs from its neighbours. How changes are found, and the largest ones.
Download the Data
Data for Chelsea standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Chelsea threshold days by year: CSV or JSON. Field meanings are on the data page.
Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-14 (14 October 2026). Records are computed by this site and are not official.