A drought is a minimum, not an average: the Thames at Kingston, 1884–2025
The gauge at Kingston has measured the Thames since October 1883. Its two lowest monthly mean flows on record both fall in 1976 — yet 1976 is only the fourth-lowest year in the same record, behind 1997, 1934 and 2005. The gap between those two facts is what an annual average does to a drought.
The finding
The two lowest monthly mean flows in the entire Kingston record both fall in 1976: 0.688 m³/s in 1976-09 and 1.912 m³/s in 1976-08, against a long-run annual mean of 65.9 m³/s. Yet 1976 is only the fourth-lowest year in that record.
| Year | Annual mean (m³/s) |
|---|---|
| 1997 | 17.56 |
| 1934 | 20.29 |
| 2005 | 20.97 |
| 1976 | 21.96 |
| Month | Monthly mean (m³/s) |
|---|---|
| 1976-09 | 0.688 |
| 1976-08 | 1.912 |
| 1921-07 | 2.079 |
| 1934-08 | 2.849 |
| 1934-09 | 3.124 |
A drought is experienced as a minimum, not as an average. 1976 had a catastrophic summer preceded by a dry winter and followed by one of the wettest autumns on record — and the autumn rain, arriving inside the same calendar year, lifted the annual mean above three other years whose dryness was less severe but more evenly spread. An annual figure is the wrong instrument for measuring a drought, and this is what that looks like in a real record.
The record
- Annual mean flow
- 10-year mean
Flow at Kingston is a property of this gauge on this reach and is affected by abstraction upstream — London's supply is taken from the river above this point, so the record measures what is left as well as what fell.
View the data behind this chart
| Period | Annual mean flow (m³/s) | 10-year mean (m³/s) |
|---|---|---|
| 1884 | 47.8 | — |
| 1885 | 58.0 | — |
| 1886 | 78.8 | — |
| 1887 | 56.3 | — |
| 1888 | 61.3 | — |
| 1889 | 64.6 | 57.6 |
| 1890 | 38.1 | 60.6 |
| 1891 | 67.9 | 60.8 |
| 1892 | 55.7 | 58.0 |
| 1893 | 47.3 | 59.7 |
| 1894 | 78.1 | 57.0 |
| 1895 | 60.0 | 55.2 |
| 1896 | 51.0 | 57.3 |
| 1897 | 73.2 | 54.6 |
| 1898 | 33.8 | 51.8 |
| 1899 | 47.3 | 58.0 |
| 1900 | 59.2 | 57.8 |
| 1901 | 40.4 | 54.8 |
| 1902 | 27.5 | 54.8 |
| 1903 | 110 | 53.4 |
| 1904 | 76.0 | 56.2 |
| 1905 | 30.4 | 57.0 |
| 1906 | 51.1 | 59.7 |
| 1907 | 58.8 | 61.3 |
| 1908 | 62.2 | 69.0 |
| 1909 | 55.0 | 66.1 |
| 1910 | 85.7 | 64.8 |
| 1911 | 56.9 | 73.1 |
| 1912 | 104 | 79.9 |
| 1913 | 81.3 | 82.0 |
| 1914 | 62.0 | 83.1 |
| 1915 | 114 | 87.4 |
| 1916 | 118 | 86.1 |
| 1917 | 80.3 | 83.3 |
| 1918 | 73.2 | 77.1 |
| 1919 | 98.2 | 76.6 |
| 1920 | 72.4 | 80.9 |
| 1921 | 28.9 | 79.0 |
| 1922 | 42.8 | 75.6 |
| 1923 | 75.9 | 78.5 |
| 1924 | 105 | 80.7 |
| 1925 | 95.8 | 76.8 |
| 1926 | 84.0 | 77.7 |
| 1927 | 109 | 82.9 |
| 1928 | 95.5 | 86.1 |
| 1929 | 59.5 | 84.5 |
| 1930 | 80.5 | 76.0 |
| 1931 | 81.5 | 73.1 |
| 1932 | 75.0 | 73.9 |
| 1933 | 59.0 | 74.4 |
| 1934 | 20.3 | 68.9 |
| 1935 | 67.1 | 72.4 |
| 1936 | 92.1 | 72.5 |
| 1937 | 113 | 72.3 |
| 1938 | 41.0 | 70.6 |
| 1939 | 94.7 | 69.6 |
| 1940 | 80.9 | 70.5 |
| 1941 | 79.3 | 67.7 |
| 1942 | 58.2 | 65.5 |
| 1943 | 49.7 | 62.5 |
| 1944 | 28.5 | 62.1 |
| 1945 | 39.4 | 56.8 |
| 1946 | 70.7 | 54.7 |
| 1947 | 82.5 | 58.9 |
| 1948 | 37.5 | 59.7 |
| 1949 | 40.8 | 58.7 |
| 1950 | 60.8 | 62.7 |
| 1951 | 121 | 64.4 |
| 1952 | 65.7 | 61.4 |
| 1953 | 39.6 | 59.1 |
| 1954 | 69.3 | 63.7 |
| 1955 | 56.2 | 66.0 |
| 1956 | 40.4 | 70.5 |
| 1957 | 59.3 | 65.4 |
| 1958 | 83.7 | 64.2 |
| 1959 | 64.3 | 66.6 |
| 1960 | 105 | 64.4 |
| 1961 | 69.9 | 63.0 |
| 1962 | 53.8 | 67.8 |
| 1963 | 63.7 | 70.2 |
| 1964 | 47.8 | 71.1 |
| 1965 | 41.8 | 71.8 |
| 1966 | 88.8 | 67.2 |
| 1967 | 83.1 | 67.4 |
| 1968 | 92.5 | 67.9 |
| 1969 | 71.7 | 63.9 |
| 1970 | 59.2 | 67.3 |
| 1971 | 71.5 | 70.0 |
| 1972 | 58.5 | 63.3 |
| 1973 | 24.1 | 63.7 |
| 1974 | 81.6 | 61.0 |
| 1975 | 68.6 | 62.2 |
| 1976 | 22.0 | 62.7 |
| 1977 | 87.7 | 62.9 |
| 1978 | 65.3 | 65.2 |
| 1979 | 83.6 | 68.6 |
| 1980 | 63.9 | 67.3 |
| 1981 | 73.8 | 66.7 |
| 1982 | 81.2 | 68.4 |
| 1983 | 58.6 | 64.2 |
| 1987 | 67.8 | 60.2 |
| 1988 | 62.7 | 56.7 |
| 1989 | 39.3 | 57.2 |
| 1990 | 45.8 | 56.5 |
| 1991 | 24.9 | 51.7 |
| 1992 | 49.2 | 47.6 |
| 1993 | 68.9 | 47.2 |
| 1995 | 67.1 | 51.6 |
| 1996 | 33.1 | 58.1 |
| 1997 | 17.6 | 61.2 |
| 1998 | 64.0 | 64.4 |
| 2000 | 107 | 64.6 |
| 2001 | 104 | 59.8 |
| 2002 | 77.0 | 62.4 |
| 2003 | 56.8 | 67.4 |
| 2004 | 50.7 | 71.5 |
| 2005 | 21.0 | 70.8 |
| 2007 | 93.5 | 63.0 |
| 2008 | 82.6 | 60.3 |
| 2009 | 58.9 | 60.7 |
| 2010 | 56.8 | 66.7 |
| 2011 | 28.6 | 65.8 |
| 2012 | 77.0 | 69.9 |
| 2013 | 81.6 | 63.6 |
| 2014 | 117 | 59.2 |
| 2015 | 40.9 | 62.0 |
| 2016 | 62.4 | 68.6 |
| 2017 | 30.5 | 71.5 |
| 2022 | 38.6 | — |
| 2023 | 86.5 | — |
| 2024 | 124 | — |
| 2025 | 56.8 | — |
Data behind this
Every figure above is computed from these datasets at build time rather than written into the text. If the underlying record changes, this page changes with it.
Citation
Hydrionis (2026), A drought is a minimum, not an average: the Thames at Kingston, 1884–2025, version 1.0. Retrieved from https://hydrionis.com/research/thames-at-kingston-flow-record/