London South Weather Records (CA006144505)

Record envelope, standing records and threshold days for London South (CA006144505), Ontario, Canada, with 50 years of record.

Key Facts for London South

London South (CA006144505) is a weather station in Ontario, Canada at 42.98 latitude and -81.22 longitude, 246 m (807 ft) above sea level.
The station reports from 1883 to 1932, 50 years of record.
1,464 records set at London South still stand.
Records are tracked for tmax, tmin, prcp, snow: an element needs 30 years of data to be eligible.
London South tied a daily record high minimum temperature of 1.1 C (34.0 F) on 20 January 1932.

About the Station

Location: Ontario, Canada, 42.98 latitude, -81.22 longitude.
Elevation: 246 m (807 ft).
Period of record: 1883 to 1932, 50 years.
Eligible elements: tmax, tmin, prcp, snow.

Daily Record Envelope and 2026

0 days at or beyond a record

The band shows the record high and record low for each calendar day at London South. 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 London South, with 2026 drawn through them
Month	Highest record high	Lowest record low	2026 highest maximum	2026 lowest minimum
Jan	16.1 C (61.0 F)	-32.2 C (-26.0 F)	n/a	n/a
Feb	15.0 C (59.0 F)	-31.7 C (-25.1 F)	n/a	n/a
Mar	26.1 C (79.0 F)	-28.3 C (-18.9 F)	n/a	n/a
Apr	30.6 C (87.1 F)	-17.8 C (0.0 F)	n/a	n/a
May	34.4 C (93.9 F)	-4.4 C (24.1 F)	n/a	n/a
Jun	37.2 C (99.0 F)	-1.1 C (30.0 F)	n/a	n/a
Jul	38.9 C (102.0 F)	2.2 C (36.0 F)	n/a	n/a
Aug	41.1 C (106.0 F)	1.7 C (35.1 F)	n/a	n/a
Sep	35.0 C (95.0 F)	-3.3 C (26.1 F)	n/a	n/a
Oct	29.4 C (84.9 F)	-10.0 C (14.0 F)	n/a	n/a
Nov	20.6 C (69.1 F)	-16.7 C (1.9 F)	n/a	n/a
Dec	14.4 C (57.9 F)	-30.0 C (-22.0 F)	n/a	n/a

Which Years Hold Standing Records

1,464 standing records

1,464 records at London South still stand. 1885 holds the most, with 57.

Standing records at London South by the year they were set
Year set	Standing records
1883	45
1884	38
1885	57
1886	33
1887	34
1888	35
1889	32
1890	21
1891	35
1892	26
1893	18
1894	37
1895	52
1896	41
1897	26
1898	29
1899	48
1900	44
1901	17
1902	31
1903	37
1904	27
1905	22
1906	27
1907	19
1908	22
1909	22
1910	20
1911	38
1912	25
1913	24
1914	31
1915	18
1916	39
1917	32
1918	28
1919	30
1920	24
1921	31
1922	20
1923	28
1924	19
1925	27
1926	18
1927	23
1928	19
1929	33
1930	33
1931	23
1932	6

All-Time Record Progression

2 new records

2 all-time records were set at London South between 6 August 1918 and 7 August 1918. Each dot is a new record.

When London South set new all-time records
Date	Kind	Detail
1918-08-06	Record high maximum temperature	Record high maximum temperature 41.1 C (106.0 F)
1918-08-07	Record high minimum temperature	Record high minimum temperature 25.6 C (78.1 F)

Wettest Day of Each Month

May: 130.0 mm (5.1 in)

The wettest day on record for each calendar month at London South. The most was 130.0 mm (5.1 in) on 17 May 1894.

Record daily precipitation for each month at London South
Month	Record daily precipitation (mm)	Date
Jan	49.5 mm (1.9 in)	29 January 1893
Feb	39.4 mm (1.6 in)	6 February 1893
Mar	40.6 mm (1.6 in)	19 March 1883
Apr	55.9 mm (2.2 in)	29 April 1909
May	130.0 mm (5.1 in)	17 May 1894
Jun	98.0 mm (3.9 in)	3 June 1892
Jul	80.0 mm (3.1 in)	10 July 1921
Aug	71.1 mm (2.8 in)	9 August 1892
Sep	44.2 mm (1.7 in)	5 September 1918
Oct	87.4 mm (3.4 in)	14 October 1893
Nov	62.7 mm (2.5 in)	22 November 1909
Dec	47.5 mm (1.9 in)	17 December 1921

Period of Record Coverage

1883 to 1932

50 years of record at London South, 1883 to 1932. 3 years have data for under 90 percent of days and are left out of rankings: 1883, 1890, 1932.

Days with data per year at London South
Year	Days with data	Share of year	Complete
1883	306	84%	No
1884	364	99%	Yes
1885	365	100%	Yes
1886	365	100%	Yes
1887	365	100%	Yes
1888	366	100%	Yes
1889	365	100%	Yes
1890	273	75%	No
1891	364	100%	Yes
1892	366	100%	Yes
1893	365	100%	Yes
1894	365	100%	Yes
1895	365	100%	Yes
1896	366	100%	Yes
1897	365	100%	Yes
1898	365	100%	Yes
1899	365	100%	Yes
1900	365	100%	Yes
1901	365	100%	Yes
1902	365	100%	Yes
1903	365	100%	Yes
1904	366	100%	Yes
1905	365	100%	Yes
1906	365	100%	Yes
1907	365	100%	Yes
1908	365	100%	Yes
1909	365	100%	Yes
1910	365	100%	Yes
1911	365	100%	Yes
1912	366	100%	Yes
1913	365	100%	Yes
1914	365	100%	Yes
1915	365	100%	Yes
1916	366	100%	Yes
1917	365	100%	Yes
1918	365	100%	Yes
1919	365	100%	Yes
1920	366	100%	Yes
1921	364	100%	Yes
1922	365	100%	Yes
1923	365	100%	Yes
1924	366	100%	Yes
1925	365	100%	Yes
1926	365	100%	Yes
1927	365	100%	Yes
1928	366	100%	Yes
1929	365	100%	Yes
1930	365	100%	Yes
1931	365	100%	Yes
1932	31	8%	No

Latest Records

Latest records at London South
Date	Station	Record	Value	Beat old record by	Old record stood	Significance
20 January 1932	London South, CA	daily high min (Tie)	1.1 C (34.0 F)	tie	31 years	3 of 100 (Routine)
17 January 1932	London South, CA	daily rain	26.4 mm (1.0 in)	5.6 mm (0.22 in)	34 years	23 of 100 (Routine)
17 January 1932	London South, CA	daily high max	10.6 C (51.1 F)	0.6 C (1.1 F)	18 years	11 of 100 (Routine)
15 January 1932	London South, CA	daily high max	10.6 C (51.1 F)	2.8 C (5.0 F)	25 years	17 of 100 (Routine)
14 January 1932	London South, CA	daily high max	14.4 C (57.9 F)	7.7 C (13.9 F)	37 years	29 of 100 (Routine)
14 January 1932	London South, CA	daily high min	5.0 C (41.0 F)	4.4 C (7.9 F)	1 year	11 of 100 (Routine)
13 January 1932	London South, CA	daily high min	8.3 C (46.9 F)	6.6 C (11.9 F)	4 years	15 of 100 (Routine)
13 January 1932	London South, CA	daily rain	19.3 mm (0.8 in)	2.8 mm (0.11 in)	13 years	13 of 100 (Routine)
12 January 1932	London South, CA	daily high max	12.2 C (54.0 F)	2.2 C (4.0 F)	41 years	20 of 100 (Routine)
24 December 1931	London South, CA	daily high min	6.7 C (44.1 F)	3.9 C (7.0 F)	37 years	21 of 100 (Routine)
23 December 1931	London South, CA	daily high min	5.0 C (41.0 F)	1.7 C (3.1 F)	37 years	17 of 100 (Routine)
24 November 1931	London South, CA	daily high max	17.2 C (63.0 F)	4.4 C (7.9 F)	22 years	18 of 100 (Routine)
24 November 1931	London South, CA	daily high min	11.1 C (52.0 F)	3.3 C (5.9 F)	22 years	16 of 100 (Routine)
23 November 1931	London South, CA	daily high min	6.7 C (44.1 F)	2.3 C (4.1 F)	4 years	9 of 100 (Routine)
23 November 1931	London South, CA	monthly high max (Tie)	20.6 C (69.1 F)	tie	22 years	5 of 100 (Routine)
20 November 1931	London South, CA	daily high max	19.4 C (66.9 F)	3.8 C (6.8 F)	30 years	20 of 100 (Routine)
17 November 1931	London South, CA	daily high max (Tie)	17.2 C (63.0 F)	tie	2 years	1 of 100 (Routine)
16 November 1931	London South, CA	daily high max	17.8 C (64.0 F)	1.1 C (2.0 F)	34 years	16 of 100 (Routine)
9 November 1931	London South, CA	daily high max	18.9 C (66.0 F)	0.6 C (1.1 F)	39 years	16 of 100 (Routine)
24 October 1931	London South, CA	daily high min	13.9 C (57.0 F)	0.6 C (1.1 F)	31 years	14 of 100 (Routine)

Climate Trend

47 complete years, 1884 to 1931

One stripe for each of 47 complete years at London South, 1884 to 1931. Blue stripes are years cooler than the station's own mean of 7.6 C (45.6 F); red stripes are warmer. The coolest year was 1885, at 5.2 C (41.3 F), and the warmest was 1921, at 9.9 C (49.8 F). The strongest colour marks a difference of 2.5 C (4.5 F).

Annual mean temperature at London South as warming stripes, 1884 to 1931
Year	Annual mean temperature	Difference from the station mean
1884	6.6 C	-0.96 C
1885	5.2 C	-2.40 C
1886	6.5 C	-1.08 C
1887	6.9 C	-0.71 C
1888	6.0 C	-1.55 C
1889	7.6 C	+0.04 C
1891	8.0 C	+0.42 C
1892	7.2 C	-0.36 C
1893	6.7 C	-0.87 C
1894	8.5 C	+0.96 C
1895	6.9 C	-0.71 C
1896	7.8 C	+0.28 C
1897	7.8 C	+0.21 C
1898	8.5 C	+0.90 C
1899	7.9 C	+0.32 C
1900	8.3 C	+0.75 C
1901	7.6 C	+0.08 C
1902	7.6 C	0.00 C
1903	7.5 C	-0.04 C
1904	5.9 C	-1.67 C
1905	7.0 C	-0.52 C
1906	8.1 C	+0.53 C
1907	6.7 C	-0.87 C
1908	8.2 C	+0.62 C
1909	8.0 C	+0.46 C
1910	7.7 C	+0.14 C
1911	8.6 C	+1.07 C
1912	7.1 C	-0.45 C
1913	8.4 C	+0.83 C
1914	7.5 C	-0.04 C
1915	7.7 C	+0.09 C
1916	7.7 C	+0.10 C
1917	5.7 C	-1.83 C
1918	8.0 C	+0.39 C
1919	8.8 C	+1.22 C
1920	7.5 C	-0.07 C
1921	9.9 C	+2.33 C
1922	8.6 C	+1.08 C
1923	7.8 C	+0.20 C
1924	6.7 C	-0.87 C
1925	7.6 C	+0.01 C
1926	6.6 C	-0.94 C
1927	8.2 C	+0.62 C
1928	7.8 C	+0.22 C
1929	7.4 C	-0.18 C
1930	8.2 C	+0.66 C
1931	9.4 C	+1.82 C

The annual mean temperature here has risen by 0.3 C (0.1 to 0.4) per decade over 1884 to 1931. In Fahrenheit: 0.5 F (0.1 to 0.8) 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 London South
Measure	Per decade (C)	Per decade (F)	Period	Complete years	Reading
Annual mean temperature	0.3 C (0.1 to 0.4) per decade	0.5 F (0.1 to 0.8) per decade	1884 to 1931	47	Rise
Mean daily maximum	0.3 C (0.1 to 0.5) per decade	0.6 F (0.2 to 0.9) per decade	1884 to 1931	47	Rise
Mean daily minimum	0.22 C (0.04 to 0.39) per decade	0.4 F (0.1 to 0.7) per decade	1884 to 1931	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

1883 to 1932

Yearly extremes at London South: the record and the median year
Measure	Record	Year of the record	Median year	Years with a value
Hottest day (TXx)	41.1 C (106.0 F)	1918	34.4 C (93.9 F)	50
Coldest night (TNn)	-32.2 C (-26.0 F)	1892	-26.7 C (-16.1 F)	50
Wettest day (Rx1day)	130.0 mm (5.1 in)	1894	44.1 mm (1.7 in)	50
Wettest five days (Rx5day)	174.5 mm (6.9 in)	1894	69.0 mm (2.7 in)	50
Longest dry spell (CDD)	35 days	1924	17 days	50

Hottest day (TXx)

The hottest day of the year at London South, 1883 to 1932. The record is 41.1 C (106.0 F) in 1918, marked on the chart; the median year is 34.4 C (93.9 F).

Hottest day (TXx) at London South by year
Year	Hottest day (TXx)
1883	31.1 C (88.0 F)
1884	31.7 C (89.1 F)
1885	30.0 C (86.0 F)
1886	32.2 C (90.0 F)
1887	35.0 C (95.0 F)
1888	31.1 C (88.0 F)
1889	31.7 C (89.1 F)
1890	30.0 C (86.0 F)
1891	34.4 C (93.9 F)
1892	33.9 C (93.0 F)
1893	33.3 C (91.9 F)
1894	35.0 C (95.0 F)
1895	34.4 C (93.9 F)
1896	33.9 C (93.0 F)
1897	35.6 C (96.1 F)
1898	36.7 C (98.1 F)
1899	35.6 C (96.1 F)
1900	35.0 C (95.0 F)
1901	36.7 C (98.1 F)
1902	32.2 C (90.0 F)
1903	32.2 C (90.0 F)
1904	33.3 C (91.9 F)
1905	32.8 C (91.0 F)
1906	32.2 C (90.0 F)
1907	30.6 C (87.1 F)
1908	35.0 C (95.0 F)
1909	34.4 C (93.9 F)
1910	36.1 C (97.0 F)
1911	38.9 C (102.0 F)
1912	33.9 C (93.0 F)
1913	34.4 C (93.9 F)
1914	35.0 C (95.0 F)
1915	31.7 C (89.1 F)
1916	37.8 C (100.0 F)
1917	36.7 C (98.1 F)
1918	41.1 C (106.0 F)
1919	36.7 C (98.1 F)
1920	34.4 C (93.9 F)
1921	37.8 C (100.0 F)
1922	35.0 C (95.0 F)
1923	36.7 C (98.1 F)
1924	34.4 C (93.9 F)
1925	37.2 C (99.0 F)
1926	36.1 C (97.0 F)
1927	36.1 C (97.0 F)
1928	32.8 C (91.0 F)
1929	34.4 C (93.9 F)
1930	35.6 C (96.1 F)
1931	37.2 C (99.0 F)
1932	14.4 C (57.9 F)

Coldest night (TNn)

The coldest night of the year at London South, 1883 to 1932. The record is -32.2 C (-26.0 F) in 1892, marked on the chart; the median year is -26.7 C (-16.1 F).

Coldest night (TNn) at London South by year
Year	Coldest night (TNn)
1883	-25.6 C (-14.1 F)
1884	-31.1 C (-24.0 F)
1885	-30.6 C (-23.1 F)
1886	-28.3 C (-18.9 F)
1887	-26.1 C (-15.0 F)
1888	-27.2 C (-17.0 F)
1889	-30.6 C (-23.1 F)
1890	-22.2 C (-8.0 F)
1891	-20.6 C (-5.1 F)
1892	-32.2 C (-26.0 F)
1893	-31.7 C (-25.1 F)
1894	-24.4 C (-11.9 F)
1895	-31.1 C (-24.0 F)
1896	-27.2 C (-17.0 F)
1897	-26.1 C (-15.0 F)
1898	-22.8 C (-9.0 F)
1899	-31.7 C (-25.1 F)
1900	-27.2 C (-17.0 F)
1901	-23.9 C (-11.0 F)
1902	-26.7 C (-16.1 F)
1903	-24.4 C (-11.9 F)
1904	-30.0 C (-22.0 F)
1905	-27.2 C (-17.0 F)
1906	-27.2 C (-17.0 F)
1907	-25.6 C (-14.1 F)
1908	-28.9 C (-20.0 F)
1909	-26.1 C (-15.0 F)
1910	-26.7 C (-16.1 F)
1911	-22.2 C (-8.0 F)
1912	-31.7 C (-25.1 F)
1913	-21.7 C (-7.1 F)
1914	-30.0 C (-22.0 F)
1915	-29.4 C (-20.9 F)
1916	-26.7 C (-16.1 F)
1917	-27.8 C (-18.0 F)
1918	-29.4 C (-20.9 F)
1919	-20.6 C (-5.1 F)
1920	-27.8 C (-18.0 F)
1921	-16.7 C (1.9 F)
1922	-20.0 C (-4.0 F)
1923	-21.7 C (-7.1 F)
1924	-25.0 C (-13.0 F)
1925	-27.8 C (-18.0 F)
1926	-22.2 C (-8.0 F)
1927	-23.9 C (-11.0 F)
1928	-27.8 C (-18.0 F)
1929	-28.9 C (-20.0 F)
1930	-22.8 C (-9.0 F)
1931	-16.7 C (1.9 F)
1932	-15.0 C (5.0 F)

Wettest day (Rx1day)

The wettest day of the year at London South, 1883 to 1932. The record is 130.0 mm (5.1 in) in 1894, marked on the chart; the median year is 44.1 mm (1.7 in).

Wettest day (Rx1day) at London South by year
Year	Wettest day (Rx1day)
1883	40.6 mm (1.6 in)
1884	38.1 mm (1.5 in)
1885	60.7 mm (2.4 in)
1886	54.6 mm (2.1 in)
1887	46.5 mm (1.8 in)
1888	64.8 mm (2.6 in)
1889	55.6 mm (2.2 in)
1890	36.3 mm (1.4 in)
1891	51.6 mm (2.0 in)
1892	98.0 mm (3.9 in)
1893	87.4 mm (3.4 in)
1894	130.0 mm (5.1 in)
1895	43.7 mm (1.7 in)
1896	47.2 mm (1.9 in)
1897	40.6 mm (1.6 in)
1898	48.3 mm (1.9 in)
1899	34.8 mm (1.4 in)
1900	38.1 mm (1.5 in)
1901	19.1 mm (0.8 in)
1902	18.0 mm (0.7 in)
1903	30.2 mm (1.2 in)
1904	58.4 mm (2.3 in)
1905	44.5 mm (1.8 in)
1906	34.3 mm (1.4 in)
1907	36.8 mm (1.4 in)
1908	43.7 mm (1.7 in)
1909	62.7 mm (2.5 in)
1910	34.3 mm (1.4 in)
1911	36.3 mm (1.4 in)
1912	43.9 mm (1.7 in)
1913	41.1 mm (1.6 in)
1914	37.1 mm (1.5 in)
1915	53.8 mm (2.1 in)
1916	62.5 mm (2.5 in)
1917	54.9 mm (2.2 in)
1918	44.2 mm (1.7 in)
1919	55.6 mm (2.2 in)
1920	40.1 mm (1.6 in)
1921	80.0 mm (3.1 in)
1922	38.1 mm (1.5 in)
1923	45.2 mm (1.8 in)
1924	36.1 mm (1.4 in)
1925	29.0 mm (1.1 in)
1926	51.8 mm (2.0 in)
1927	38.1 mm (1.5 in)
1928	51.3 mm (2.0 in)
1929	36.6 mm (1.4 in)
1930	55.1 mm (2.2 in)
1931	49.8 mm (2.0 in)
1932	26.4 mm (1.0 in)

Wettest five days (Rx5day)

The wettest five days of the year at London South, 1883 to 1932. The record is 174.5 mm (6.9 in) in 1894, marked on the chart; the median year is 69.0 mm (2.7 in).

Wettest five days (Rx5day) at London South by year
Year	Wettest five days (Rx5day)
1883	94.0 mm (3.7 in)
1884	66.0 mm (2.6 in)
1885	74.9 mm (2.9 in)
1886	59.5 mm (2.3 in)
1887	85.6 mm (3.4 in)
1888	103.9 mm (4.1 in)
1889	91.7 mm (3.6 in)
1890	66.8 mm (2.6 in)
1891	86.9 mm (3.4 in)
1892	134.0 mm (5.3 in)
1893	98.6 mm (3.9 in)
1894	174.5 mm (6.9 in)
1895	55.2 mm (2.2 in)
1896	81.7 mm (3.2 in)
1897	56.6 mm (2.2 in)
1898	74.3 mm (2.9 in)
1899	67.3 mm (2.6 in)
1900	64.9 mm (2.6 in)
1901	34.9 mm (1.4 in)
1902	38.1 mm (1.5 in)
1903	49.1 mm (1.9 in)
1904	69.1 mm (2.7 in)
1905	66.5 mm (2.6 in)
1906	77.5 mm (3.1 in)
1907	57.6 mm (2.3 in)
1908	55.9 mm (2.2 in)
1909	102.6 mm (4.0 in)
1910	80.9 mm (3.2 in)
1911	68.6 mm (2.7 in)
1912	75.2 mm (3.0 in)
1913	80.9 mm (3.2 in)
1914	54.6 mm (2.1 in)
1915	106.2 mm (4.2 in)
1916	62.5 mm (2.5 in)
1917	68.9 mm (2.7 in)
1918	61.4 mm (2.4 in)
1919	99.7 mm (3.9 in)
1920	58.9 mm (2.3 in)
1921	107.2 mm (4.2 in)
1922	79.5 mm (3.1 in)
1923	61.0 mm (2.4 in)
1924	60.7 mm (2.4 in)
1925	68.6 mm (2.7 in)
1926	67.3 mm (2.6 in)
1927	73.4 mm (2.9 in)
1928	63.7 mm (2.5 in)
1929	88.4 mm (3.5 in)
1930	80.9 mm (3.2 in)
1931	85.9 mm (3.4 in)
1932	50.8 mm (2.0 in)

Longest dry spell (CDD)

The longest dry spell of the year at London South, 1883 to 1932. The record is 35 days in 1924, marked on the chart; the median year is 17 days.

Longest dry spell (CDD) at London South by year
Year	Longest dry spell (CDD)
1883	14 days
1884	14 days
1885	18 days
1886	20 days
1887	28 days
1888	21 days
1889	26 days
1890	16 days
1891	22 days
1892	24 days
1893	12 days
1894	26 days
1895	18 days
1896	13 days
1897	20 days
1898	14 days
1899	20 days
1900	15 days
1901	16 days
1902	21 days
1903	14 days
1904	17 days
1905	11 days
1906	25 days
1907	15 days
1908	25 days
1909	20 days
1910	16 days
1911	17 days
1912	14 days
1913	20 days
1914	15 days
1915	19 days
1916	30 days
1917	19 days
1918	17 days
1919	16 days
1920	12 days
1921	25 days
1922	17 days
1923	15 days
1924	35 days
1925	15 days
1926	14 days
1927	13 days
1928	10 days
1929	19 days
1930	18 days
1931	10 days
1932	4 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

47 years with a frost

Across 47 years with a frost, the median last spring frost at London South falls on 17 May and the median first autumn frost on 1 October, which leaves a median of 136 days between them.

Fitted over all years, the growing season changes by -2.3 days per decade at this station.

Frost dates and growing season at London South
Measure	Median, all years	Earliest period	Recent period (1902 to 1931)	Recent against earliest	Fitted trend
Last spring frost	17 May	n/a	18 May	n/a	+1.0 days per decade
First autumn frost	1 October	n/a	29 September	n/a	-1.4 days per decade
Growing days	136 days	n/a	134 days	n/a	-2.3 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

47 years, 1884 to 1931

A day with at least 44.6 mm (1.8 in) of rain is expected about once in 2 years. A day with at least 118.1 mm (4.6 in) of rain is expected about once in 100 years.

Rainfall return levels at London South: the daily rain expected about once in a given number of years
Expected about once in	A day with at least	Note
2 years	44.6 mm (1.8 in)
5 years	60.0 mm (2.4 in)
10 years	71.8 mm (2.8 in)
25 years	88.5 mm (3.5 in)
50 years	102.6 mm (4.0 in)	Longer than the 47 years of record
100 years	118.1 mm (4.6 in)	Longer than the 47 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, 47 years of values from 1884 to 1931.

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: 130.0 mm (5.1 in) in 1894; 98.0 mm (3.9 in) in 1892; 87.4 mm (3.4 in) in 1893.

Station Changes

No change in the annual mean temperature of this station was found against its neighbours.

Download the Data

Data for London South standing records by year: CSV or JSON. Field meanings are on the data page.
Data for London South 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 2026-10-17 (17 October 2026). Records are computed by this site and are not official.

Data as of 2026-10-17. Last revised 17 October 2026 (2026-10-17).