Record highRecord low2026 daily maximum2026 daily minimum
The band shows the record high and record low for each calendar day at Swansea Post Office. 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 Swansea Post Office, with 2026 drawn through them
Month
Highest record high
Lowest record low
2026 highest maximum
2026 lowest minimum
Jan
40.4 C (104.7 F)
2.4 C (36.3 F)
n/a
n/a
Feb
39.2 C (102.6 F)
1.3 C (34.3 F)
n/a
n/a
Mar
36.8 C (98.2 F)
0.0 C (32.0 F)
n/a
n/a
Apr
30.1 C (86.2 F)
-1.3 C (29.7 F)
n/a
n/a
May
27.0 C (80.6 F)
-3.1 C (26.4 F)
n/a
n/a
Jun
21.1 C (70.0 F)
-4.0 C (24.8 F)
n/a
n/a
Jul
24.0 C (75.2 F)
-5.0 C (23.0 F)
n/a
n/a
Aug
24.3 C (75.7 F)
-4.2 C (24.4 F)
n/a
n/a
Sep
29.6 C (85.3 F)
-4.0 C (24.8 F)
n/a
n/a
Oct
33.9 C (93.0 F)
-1.9 C (28.6 F)
n/a
n/a
Nov
36.0 C (96.8 F)
-1.4 C (29.5 F)
n/a
n/a
Dec
38.1 C (100.6 F)
1.0 C (33.8 F)
n/a
n/a
Which Years Hold Standing Records
1,464 standing records
Year with most
1,464 records at Swansea Post Office still stand. 1976 holds the most, with 51.
Standing records at Swansea Post Office by the year they were set
Year set
Standing records
1957
31
1958
41
1959
30
1960
22
1961
24
1962
45
1963
32
1964
39
1965
35
1966
31
1967
20
1968
22
1969
24
1970
24
1971
14
1972
26
1973
18
1974
15
1975
28
1976
51
1977
37
1978
48
1979
48
1980
40
1981
24
1982
36
1983
33
1984
22
1985
21
1986
13
1987
27
1988
21
1989
15
1990
26
1991
20
1992
21
1993
17
1994
44
1995
27
1996
20
1997
24
1998
24
1999
22
2000
26
2001
17
2002
19
2003
22
2004
13
2005
29
2006
23
2007
23
2008
23
2009
29
2010
29
2011
9
All-Time Record Progression
4 new records
4 all-time records were set at Swansea Post Office between 7 June 1954 and 25 January 2003. Each dot is a new record.
When Swansea Post Office set new all-time records
Date
Kind
Detail
1954-06-07
Record daily precipitation
Record daily precipitation 172.5 mm (6.8 in)
1988-01-30
Record high minimum temperature
Record high minimum temperature 21.3 C (70.3 F)
1999-12-03
Record high minimum temperature
Record high minimum temperature 22.1 C (71.8 F)
2003-01-25
Record high maximum temperature
Record high maximum temperature 40.4 C (104.7 F)
Wettest Day of Each Month
Jun: 172.5 mm (6.8 in)
The wettest day on record for each calendar month at Swansea Post Office. The most was 172.5 mm (6.8 in) on 7 June 1954.
Record daily precipitation for each month at Swansea Post Office
Month
Record daily precipitation (mm)
Date
Jan
109.6 mm (4.3 in)
29 January 1995
Feb
115.6 mm (4.6 in)
19 February 1946
Mar
116.3 mm (4.6 in)
16 March 1946
Apr
121.4 mm (4.8 in)
23 April 1960
May
131.6 mm (5.2 in)
29 May 2010
Jun
172.5 mm (6.8 in)
7 June 1954
Jul
107.4 mm (4.2 in)
8 July 1891
Aug
72.4 mm (2.9 in)
1 August 1994
Sep
69.6 mm (2.7 in)
20 September 1959
Oct
75.4 mm (3.0 in)
9 October 2005
Nov
97.0 mm (3.8 in)
29 November 1889
Dec
103.4 mm (4.1 in)
19 December 1995
Period of Record Coverage
1957 to 2011
Complete yearUnder 90 percent of days
55 years of record at Swansea Post Office, 1957 to 2011. 7 years have data for under 90 percent of days and are left out of rankings: 1968, 1969, 1970, 1971, 1972, 1973, 2011.
Cooler than the station meanWarmer than the station mean
One stripe for each of 47 complete years at Swansea Post Office, 1957 to 2010. Blue stripes are years cooler than the station's own mean of 12.9 C (55.1 F); red stripes are warmer. The coolest year was 1964, at 11.7 C (53.0 F), and the warmest was 2007, at 13.7 C (56.7 F). The strongest colour marks a difference of 1.2 C (2.2 F).
Annual mean temperature at Swansea Post Office as warming stripes, 1957 to 2010
Year
Annual mean temperature
Difference from the station mean
1957
12.3 C
-0.55 C
1958
12.0 C
-0.84 C
1959
12.6 C
-0.29 C
1960
12.4 C
-0.50 C
1961
13.1 C
+0.21 C
1962
12.5 C
-0.41 C
1964
11.7 C
-1.19 C
1965
12.2 C
-0.66 C
1969
12.7 C
-0.17 C
1973
13.4 C
+0.52 C
1974
13.0 C
+0.16 C
1975
12.7 C
-0.14 C
1976
11.9 C
-0.97 C
1977
12.1 C
-0.75 C
1978
12.2 C
-0.67 C
1979
12.3 C
-0.53 C
1980
12.9 C
+0.08 C
1981
13.3 C
+0.48 C
1982
13.3 C
+0.43 C
1983
12.6 C
-0.22 C
1984
13.0 C
+0.16 C
1985
12.6 C
-0.31 C
1986
12.6 C
-0.30 C
1987
12.8 C
-0.02 C
1988
13.7 C
+0.87 C
1989
13.0 C
+0.15 C
1990
13.2 C
+0.29 C
1991
13.0 C
+0.17 C
1992
12.5 C
-0.34 C
1993
13.4 C
+0.53 C
1994
13.1 C
+0.23 C
1995
12.3 C
-0.58 C
1996
12.5 C
-0.41 C
1997
13.1 C
+0.25 C
1998
13.2 C
+0.32 C
1999
13.6 C
+0.69 C
2000
13.6 C
+0.70 C
2001
13.5 C
+0.63 C
2002
13.6 C
+0.73 C
2003
13.3 C
+0.39 C
2004
12.7 C
-0.14 C
2005
13.6 C
+0.69 C
2006
12.9 C
-0.01 C
2007
13.7 C
+0.87 C
2008
12.9 C
-0.01 C
2009
13.1 C
+0.28 C
2010
12.9 C
+0.03 C
The annual mean temperature here has risen by 0.2 C (0.1 to 0.3) per decade over 1957 to 2010. In Fahrenheit: 0.3 F (0.2 to 0.5) per decade. The slope is a straight line fitted to 47 complete years; the brackets give its 95 percent interval.
Fitted temperature trends per decade at Swansea Post Office
Measure
Per decade (C)
Per decade (F)
Period
Complete years
Reading
Annual mean temperature
0.2 C (0.1 to 0.3) per decade
0.3 F (0.2 to 0.5) per decade
1957 to 2010
47
Rise
Mean daily maximum
0.2 C (0.1 to 0.3) per decade
0.4 F (0.2 to 0.5) per decade
1957 to 2010
47
Rise
Mean daily minimum
0.2 C (0.1 to 0.3) per decade
0.3 F (0.1 to 0.5) per decade
1957 to 2010
47
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
1885 to 2011
Yearly extremes at Swansea Post Office: the record and the median year
Measure
Record
Year of the record
Median year
Years with a value
Hottest day (TXx)
40.4 C (104.7 F)
2003
35.0 C (95.0 F)
55
Coldest night (TNn)
-5.0 C (23.0 F)
1979
-1.8 C (28.8 F)
55
Wettest day (Rx1day)
172.5 mm (6.8 in)
1954
51.8 mm (2.0 in)
113
Wettest five days (Rx5day)
240.1 mm (9.5 in)
1954
77.2 mm (3.0 in)
113
Longest dry spell (CDD)
58 days
1959
24 days
113
Hottest day (TXx)
The hottest day of the year at Swansea Post Office, 1885 to 2011. The record is 40.4 C (104.7 F) in 2003, marked on the chart; the median year is 35.0 C (95.0 F).
Hottest day (TXx) at Swansea Post Office by year
Year
Hottest day (TXx)
1885
n/a
1888
n/a
1889
n/a
1890
n/a
1891
n/a
1892
n/a
1893
n/a
1900
n/a
1904
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1919
n/a
1920
n/a
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1925
n/a
1926
n/a
1927
n/a
1928
n/a
1929
n/a
1930
n/a
1931
n/a
1932
n/a
1933
n/a
1934
n/a
1935
n/a
1936
n/a
1937
n/a
1938
n/a
1939
n/a
1940
n/a
1941
n/a
1942
n/a
1943
n/a
1944
n/a
1945
n/a
1946
n/a
1947
n/a
1948
n/a
1949
n/a
1950
n/a
1952
n/a
1953
n/a
1954
n/a
1955
n/a
1956
n/a
1957
35.0 C (95.0 F)
1958
32.8 C (91.0 F)
1959
38.3 C (100.9 F)
1960
36.8 C (98.2 F)
1961
33.4 C (92.1 F)
1962
35.6 C (96.1 F)
1963
32.2 C (90.0 F)
1964
34.4 C (93.9 F)
1965
35.0 C (95.0 F)
1966
35.0 C (95.0 F)
1967
31.1 C (88.0 F)
1968
38.9 C (102.0 F)
1969
34.2 C (93.6 F)
1970
29.0 C (84.2 F)
1971
33.3 C (91.9 F)
1972
34.6 C (94.3 F)
1973
35.1 C (95.2 F)
1974
33.7 C (92.7 F)
1975
36.2 C (97.2 F)
1976
36.5 C (97.7 F)
1977
31.2 C (88.2 F)
1978
36.4 C (97.5 F)
1979
33.9 C (93.0 F)
1980
34.7 C (94.5 F)
1981
35.6 C (96.1 F)
1982
39.2 C (102.6 F)
1983
39.1 C (102.4 F)
1984
34.3 C (93.7 F)
1985
36.6 C (97.9 F)
1986
34.9 C (94.8 F)
1987
34.8 C (94.6 F)
1988
37.6 C (99.7 F)
1989
36.7 C (98.1 F)
1990
35.9 C (96.6 F)
1991
39.2 C (102.6 F)
1992
32.2 C (90.0 F)
1993
35.8 C (96.4 F)
1994
38.1 C (100.6 F)
1995
37.0 C (98.6 F)
1996
32.4 C (90.3 F)
1997
38.5 C (101.3 F)
1998
36.4 C (97.5 F)
1999
34.9 C (94.8 F)
2000
35.7 C (96.3 F)
2001
37.9 C (100.2 F)
2002
32.4 C (90.3 F)
2003
40.4 C (104.7 F)
2004
33.1 C (91.6 F)
2005
33.6 C (92.5 F)
2006
37.3 C (99.1 F)
2007
35.0 C (95.0 F)
2008
36.8 C (98.2 F)
2009
39.8 C (103.6 F)
2010
33.3 C (91.9 F)
2011
31.5 C (88.7 F)
Coldest night (TNn)
The coldest night of the year at Swansea Post Office, 1885 to 2011. The record is -5.0 C (23.0 F) in 1979, marked on the chart; the median year is -1.8 C (28.8 F).
Coldest night (TNn) at Swansea Post Office by year
Year
Coldest night (TNn)
1885
n/a
1888
n/a
1889
n/a
1890
n/a
1891
n/a
1892
n/a
1893
n/a
1900
n/a
1904
n/a
1907
n/a
1908
n/a
1909
n/a
1910
n/a
1911
n/a
1912
n/a
1913
n/a
1914
n/a
1915
n/a
1916
n/a
1917
n/a
1918
n/a
1919
n/a
1920
n/a
1921
n/a
1922
n/a
1923
n/a
1924
n/a
1925
n/a
1926
n/a
1927
n/a
1928
n/a
1929
n/a
1930
n/a
1931
n/a
1932
n/a
1933
n/a
1934
n/a
1935
n/a
1936
n/a
1937
n/a
1938
n/a
1939
n/a
1940
n/a
1941
n/a
1942
n/a
1943
n/a
1944
n/a
1945
n/a
1946
n/a
1947
n/a
1948
n/a
1949
n/a
1950
n/a
1952
n/a
1953
n/a
1954
n/a
1955
n/a
1956
n/a
1957
-1.7 C (28.9 F)
1958
-2.8 C (27.0 F)
1959
-2.8 C (27.0 F)
1960
-1.9 C (28.6 F)
1961
-2.3 C (27.9 F)
1962
-2.3 C (27.9 F)
1963
-2.5 C (27.5 F)
1964
-2.8 C (27.0 F)
1965
-3.3 C (26.1 F)
1966
-3.3 C (26.1 F)
1967
-1.1 C (30.0 F)
1968
-2.7 C (27.1 F)
1969
-0.6 C (30.9 F)
1970
-0.6 C (30.9 F)
1971
-3.3 C (26.1 F)
1972
-2.9 C (26.8 F)
1973
-2.1 C (28.2 F)
1974
-0.3 C (31.5 F)
1975
-1.9 C (28.6 F)
1976
-3.9 C (25.0 F)
1977
-4.0 C (24.8 F)
1978
-4.2 C (24.4 F)
1979
-5.0 C (23.0 F)
1980
-2.4 C (27.7 F)
1981
-1.0 C (30.2 F)
1982
-1.5 C (29.3 F)
1983
-4.0 C (24.8 F)
1984
-1.5 C (29.3 F)
1985
-3.5 C (25.7 F)
1986
-1.8 C (28.8 F)
1987
-1.8 C (28.8 F)
1988
-0.3 C (31.5 F)
1989
-1.5 C (29.3 F)
1990
-1.9 C (28.6 F)
1991
-1.2 C (29.8 F)
1992
-1.7 C (28.9 F)
1993
-1.7 C (28.9 F)
1994
-3.2 C (26.2 F)
1995
-2.2 C (28.0 F)
1996
-1.2 C (29.8 F)
1997
-1.5 C (29.3 F)
1998
-0.5 C (31.1 F)
1999
-1.8 C (28.8 F)
2000
-1.2 C (29.8 F)
2001
-0.7 C (30.7 F)
2002
-2.0 C (28.4 F)
2003
-0.8 C (30.6 F)
2004
-2.2 C (28.0 F)
2005
-1.4 C (29.5 F)
2006
-1.7 C (28.9 F)
2007
-1.5 C (29.3 F)
2008
-1.5 C (29.3 F)
2009
-1.8 C (28.8 F)
2010
-2.5 C (27.5 F)
2011
1.5 C (34.7 F)
Wettest day (Rx1day)
The wettest day of the year at Swansea Post Office, 1885 to 2011. The record is 172.5 mm (6.8 in) in 1954, marked on the chart; the median year is 51.8 mm (2.0 in).
Wettest day (Rx1day) at Swansea Post Office by year
Year
Wettest day (Rx1day)
1885
47.8 mm (1.9 in)
1888
42.7 mm (1.7 in)
1889
125.0 mm (4.9 in)
1890
102.1 mm (4.0 in)
1891
107.4 mm (4.2 in)
1892
6.9 mm (0.27 in)
1893
71.4 mm (2.8 in)
1900
0.0 mm (0.00 in)
1904
37.6 mm (1.5 in)
1907
38.1 mm (1.5 in)
1908
31.8 mm (1.3 in)
1909
59.2 mm (2.3 in)
1910
39.4 mm (1.6 in)
1911
91.4 mm (3.6 in)
1912
51.8 mm (2.0 in)
1913
18.3 mm (0.7 in)
1914
38.1 mm (1.5 in)
1915
37.6 mm (1.5 in)
1916
54.6 mm (2.1 in)
1917
118.1 mm (4.6 in)
1918
41.9 mm (1.6 in)
1919
63.2 mm (2.5 in)
1920
42.4 mm (1.7 in)
1921
33.5 mm (1.3 in)
1922
107.4 mm (4.2 in)
1923
159.5 mm (6.3 in)
1924
40.9 mm (1.6 in)
1925
52.3 mm (2.1 in)
1926
41.4 mm (1.6 in)
1927
68.1 mm (2.7 in)
1928
83.8 mm (3.3 in)
1929
69.3 mm (2.7 in)
1930
36.6 mm (1.4 in)
1931
74.7 mm (2.9 in)
1932
42.4 mm (1.7 in)
1933
37.6 mm (1.5 in)
1934
69.6 mm (2.7 in)
1935
81.3 mm (3.2 in)
1936
53.1 mm (2.1 in)
1937
50.0 mm (2.0 in)
1938
100.8 mm (4.0 in)
1939
38.4 mm (1.5 in)
1940
28.7 mm (1.1 in)
1941
60.5 mm (2.4 in)
1942
36.8 mm (1.4 in)
1943
75.2 mm (3.0 in)
1944
54.9 mm (2.2 in)
1945
47.8 mm (1.9 in)
1946
116.3 mm (4.6 in)
1947
74.7 mm (2.9 in)
1948
37.8 mm (1.5 in)
1949
34.0 mm (1.3 in)
1950
45.5 mm (1.8 in)
1952
33.8 mm (1.3 in)
1953
30.7 mm (1.2 in)
1954
172.5 mm (6.8 in)
1955
34.5 mm (1.4 in)
1956
51.3 mm (2.0 in)
1957
57.2 mm (2.3 in)
1958
69.6 mm (2.7 in)
1959
69.6 mm (2.7 in)
1960
121.4 mm (4.8 in)
1961
20.3 mm (0.8 in)
1962
62.0 mm (2.4 in)
1963
29.7 mm (1.2 in)
1964
63.8 mm (2.5 in)
1965
29.2 mm (1.1 in)
1966
54.9 mm (2.2 in)
1967
36.3 mm (1.4 in)
1968
46.2 mm (1.8 in)
1969
104.9 mm (4.1 in)
1970
75.9 mm (3.0 in)
1971
35.8 mm (1.4 in)
1972
28.7 mm (1.1 in)
1973
53.3 mm (2.1 in)
1974
42.4 mm (1.7 in)
1975
52.6 mm (2.1 in)
1976
42.0 mm (1.7 in)
1977
32.2 mm (1.3 in)
1978
59.4 mm (2.3 in)
1979
22.6 mm (0.9 in)
1980
64.6 mm (2.5 in)
1981
50.1 mm (2.0 in)
1982
59.2 mm (2.3 in)
1983
65.6 mm (2.6 in)
1984
65.4 mm (2.6 in)
1985
38.6 mm (1.5 in)
1986
46.8 mm (1.8 in)
1987
56.8 mm (2.2 in)
1988
53.6 mm (2.1 in)
1989
46.2 mm (1.8 in)
1990
35.2 mm (1.4 in)
1991
27.4 mm (1.1 in)
1992
44.2 mm (1.7 in)
1993
63.2 mm (2.5 in)
1994
72.4 mm (2.9 in)
1995
109.6 mm (4.3 in)
1996
73.2 mm (2.9 in)
1997
40.0 mm (1.6 in)
1998
42.4 mm (1.7 in)
1999
55.2 mm (2.2 in)
2000
93.2 mm (3.7 in)
2001
41.2 mm (1.6 in)
2002
31.0 mm (1.2 in)
2003
68.6 mm (2.7 in)
2004
102.0 mm (4.0 in)
2005
75.4 mm (3.0 in)
2006
26.6 mm (1.0 in)
2007
27.6 mm (1.1 in)
2008
33.8 mm (1.3 in)
2009
83.4 mm (3.3 in)
2010
131.6 mm (5.2 in)
2011
67.0 mm (2.6 in)
Wettest five days (Rx5day)
The wettest five days of the year at Swansea Post Office, 1885 to 2011. The record is 240.1 mm (9.5 in) in 1954, marked on the chart; the median year is 77.2 mm (3.0 in).
Wettest five days (Rx5day) at Swansea Post Office by year
Year
Wettest five days (Rx5day)
1885
60.2 mm (2.4 in)
1888
67.3 mm (2.6 in)
1889
219.2 mm (8.6 in)
1890
130.8 mm (5.1 in)
1891
214.2 mm (8.4 in)
1892
6.9 mm (0.27 in)
1893
180.3 mm (7.1 in)
1900
0.0 mm (0.00 in)
1904
59.7 mm (2.4 in)
1907
41.4 mm (1.6 in)
1908
48.1 mm (1.9 in)
1909
63.3 mm (2.5 in)
1910
76.8 mm (3.0 in)
1911
164.4 mm (6.5 in)
1912
70.0 mm (2.8 in)
1913
33.5 mm (1.3 in)
1914
78.0 mm (3.1 in)
1915
58.5 mm (2.3 in)
1916
70.6 mm (2.8 in)
1917
129.8 mm (5.1 in)
1918
61.3 mm (2.4 in)
1919
119.7 mm (4.7 in)
1920
62.3 mm (2.5 in)
1921
37.4 mm (1.5 in)
1922
153.1 mm (6.0 in)
1923
193.6 mm (7.6 in)
1924
103.4 mm (4.1 in)
1925
115.3 mm (4.5 in)
1926
87.5 mm (3.4 in)
1927
80.0 mm (3.1 in)
1928
133.6 mm (5.3 in)
1929
106.9 mm (4.2 in)
1930
61.0 mm (2.4 in)
1931
92.7 mm (3.6 in)
1932
77.7 mm (3.1 in)
1933
56.9 mm (2.2 in)
1934
119.1 mm (4.7 in)
1935
173.7 mm (6.8 in)
1936
55.7 mm (2.2 in)
1937
83.0 mm (3.3 in)
1938
161.0 mm (6.3 in)
1939
77.5 mm (3.1 in)
1940
44.5 mm (1.8 in)
1941
122.7 mm (4.8 in)
1942
51.9 mm (2.0 in)
1943
149.4 mm (5.9 in)
1944
67.6 mm (2.7 in)
1945
69.4 mm (2.7 in)
1946
170.9 mm (6.7 in)
1947
92.0 mm (3.6 in)
1948
51.1 mm (2.0 in)
1949
43.1 mm (1.7 in)
1950
70.1 mm (2.8 in)
1952
64.3 mm (2.5 in)
1953
57.6 mm (2.3 in)
1954
240.1 mm (9.5 in)
1955
58.6 mm (2.3 in)
1956
107.7 mm (4.2 in)
1957
86.1 mm (3.4 in)
1958
103.5 mm (4.1 in)
1959
124.9 mm (4.9 in)
1960
207.5 mm (8.2 in)
1961
35.5 mm (1.4 in)
1962
74.2 mm (2.9 in)
1963
37.8 mm (1.5 in)
1964
74.5 mm (2.9 in)
1965
79.0 mm (3.1 in)
1966
91.2 mm (3.6 in)
1967
75.7 mm (3.0 in)
1968
52.8 mm (2.1 in)
1969
161.3 mm (6.4 in)
1970
118.7 mm (4.7 in)
1971
85.9 mm (3.4 in)
1972
46.3 mm (1.8 in)
1973
65.8 mm (2.6 in)
1974
128.0 mm (5.0 in)
1975
62.4 mm (2.5 in)
1976
62.8 mm (2.5 in)
1977
57.0 mm (2.2 in)
1978
106.6 mm (4.2 in)
1979
33.8 mm (1.3 in)
1980
77.2 mm (3.0 in)
1981
124.9 mm (4.9 in)
1982
113.0 mm (4.4 in)
1983
76.8 mm (3.0 in)
1984
81.7 mm (3.2 in)
1985
119.6 mm (4.7 in)
1986
89.6 mm (3.5 in)
1987
66.6 mm (2.6 in)
1988
61.6 mm (2.4 in)
1989
48.0 mm (1.9 in)
1990
62.6 mm (2.5 in)
1991
60.2 mm (2.4 in)
1992
50.8 mm (2.0 in)
1993
180.2 mm (7.1 in)
1994
133.8 mm (5.3 in)
1995
141.8 mm (5.6 in)
1996
76.0 mm (3.0 in)
1997
46.0 mm (1.8 in)
1998
95.8 mm (3.8 in)
1999
66.8 mm (2.6 in)
2000
110.4 mm (4.3 in)
2001
59.6 mm (2.3 in)
2002
33.0 mm (1.3 in)
2003
94.6 mm (3.7 in)
2004
162.2 mm (6.4 in)
2005
103.2 mm (4.1 in)
2006
37.8 mm (1.5 in)
2007
39.8 mm (1.6 in)
2008
53.2 mm (2.1 in)
2009
109.8 mm (4.3 in)
2010
146.2 mm (5.8 in)
2011
144.8 mm (5.7 in)
Longest dry spell (CDD)
The longest dry spell of the year at Swansea Post Office, 1885 to 2011. The record is 58 days in 1959, marked on the chart; the median year is 24 days.
Longest dry spell (CDD) at Swansea Post Office by year
Year
Longest dry spell (CDD)
1885
15 days
1888
29 days
1889
12 days
1890
20 days
1891
17 days
1892
24 days
1893
30 days
1900
28 days
1904
37 days
1907
20 days
1908
38 days
1909
19 days
1910
44 days
1911
32 days
1912
22 days
1913
20 days
1914
38 days
1915
20 days
1916
32 days
1917
18 days
1918
17 days
1919
23 days
1920
32 days
1921
19 days
1922
31 days
1923
23 days
1924
15 days
1925
14 days
1926
28 days
1927
25 days
1928
19 days
1929
17 days
1930
28 days
1931
24 days
1932
43 days
1933
29 days
1934
20 days
1935
26 days
1936
16 days
1937
29 days
1938
21 days
1939
34 days
1940
19 days
1941
29 days
1942
24 days
1943
30 days
1944
30 days
1945
24 days
1946
24 days
1947
29 days
1948
19 days
1949
19 days
1950
23 days
1952
18 days
1953
24 days
1954
25 days
1955
29 days
1956
14 days
1957
27 days
1958
19 days
1959
58 days
1960
16 days
1961
22 days
1962
19 days
1963
16 days
1964
14 days
1965
27 days
1966
30 days
1967
43 days
1968
18 days
1969
21 days
1970
19 days
1971
26 days
1972
31 days
1973
18 days
1974
12 days
1975
25 days
1976
33 days
1977
31 days
1978
20 days
1979
22 days
1980
42 days
1981
32 days
1982
31 days
1983
27 days
1984
24 days
1985
19 days
1986
27 days
1987
30 days
1988
25 days
1989
13 days
1990
23 days
1991
27 days
1992
21 days
1993
24 days
1994
24 days
1995
30 days
1996
28 days
1997
29 days
1998
37 days
1999
25 days
2000
28 days
2001
17 days
2002
22 days
2003
22 days
2004
19 days
2005
25 days
2006
34 days
2007
21 days
2008
30 days
2009
15 days
2010
22 days
2011
13 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
45 years with a frost
Across 45 years with a frost, the median last spring frost at Swansea Post Office falls on 10 September and the median first autumn frost on 23 May, which leaves a median of 275 days between them.
Fitted over all years, the growing season changes by +12.0 days per decade at this station.
Frost dates and growing season at Swansea Post Office
Measure
Median, all years
Earliest period
Recent period (1979 to 2009)
Recent against earliest
Fitted trend
Last spring frost
10 September
n/a
30 August
n/a
-8.2 days per decade
First autumn frost
23 May
n/a
3 June
n/a
+3.8 days per decade
Growing days
275 days
n/a
284 days
n/a
+12.0 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
101 years, 1904 to 2010
A day with at least 50.7 mm (2.0 in) of rain is expected about once in 2 years. A day with at least 154.7 mm (6.1 in) of rain is expected about once in 100 years.
Rainfall return levels at Swansea Post Office: the daily rain expected about once in a given number of years
Expected about once in
A day with at least
Note
2 years
50.7 mm (2.0 in)
5 years
73.3 mm (2.9 in)
10 years
90.2 mm (3.6 in)
25 years
114.0 mm (4.5 in)
50 years
133.5 mm (5.3 in)
100 years
154.7 mm (6.1 in)
The levels come from a generalised extreme value (GEV) distribution fitted by L-moments to the wettest-day total of each year, 101 years of values from 1904 to 2010.
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: 159.5 mm (6.3 in) in 1923; 131.6 mm (5.2 in) in 2010; 121.4 mm (4.8 in) in 1960.
Station Changes
1 suspected
One change was suspected in the annual mean temperature of Swansea Post Office, at 1981. Each is measured against neighbouring stations.
Relative to 5 neighbouring stations, the station's annual mean temperature from 1981 ran 0.3 C (0.5 F) higher than in the years before (likely change).
Suspected changes in the annual mean temperature at Swansea Post Office, against neighbouring stations
Year
Shift (C)
Shift (F)
Strength
Neighbours
1981
+0.3
+0.5
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 Swansea Post Office standing records by year: CSV or JSON. Field meanings are on the data page.
Data for Swansea Post Office 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 2026-10-13 (13 October 2026). Records are computed by this site and are not official.