Updated: 2026-07-31
The closest meteorological monitoring point to London is the High Beach station in the county of Essex, situated at an altitude of 110 metres and located approximately 20.8 km from the city centre. The data presented here reflects what this station has recorded; local conditions in London itself may vary due to differences in altitude, proximity to the River Thames, or urban heat island effects. This record is the best available reference, though not an exact measurement for every neighbourhood of London.
December 1989 stands as the wettest December on record at this station. The total accumulated rainfall for that month reached 143.4 mm — the highest December total recorded between 1978 and 2025. The single heaviest day within that month, and indeed within any December in the entire series, occurred on 14 December 1989, when 29.5 mm of rain fell in one day.
That December of 1989 has not been beaten in the decades since. The runner-up, December 1978, accumulated 132.4 mm, a full 11.0 mm below the record. No other December in the series has even approached 120 mm. The gap between first and second place underlines how exceptional that month was — a sustained period of wet weather rather than a single freak storm, since the monthly total came from many days of rain.
To put the record day into perspective: 29.5 mm falling on 14 December 1989 is the largest single-day December rainfall measured at this station across the entire 1978–2025 period. It stands alone as the wettest December day, with the next highest daily amount being 28.7 mm, recorded in December 1995 — a difference of just 0.8 mm. The record could have fallen on that later date, but it did not.
The following table lists the five Decembers with the highest total precipitation in the station's complete record. These are the only five years in the series where December rainfall exceeded 90 mm.
| Year | December Total Precipitation (mm) |
|---|---|
| 1989 | 143.4 |
| 1978 | 132.4 |
| 2012 | 104.5 |
| 1979 | 94.0 |
| 1993 | 93.0 |
Notice the sharp drop after the top two: 2012's 104.5 mm, while still a very wet December, sits more than 38 mm below the 1989 record. The list also shows that notably wet Decembers are not confined to any single era — they appear in the late 1970s, the early 1990s, and as recently as 2012.
The complete series from 1978 through 2025 shows how variable December can be. Some years record almost nothing — December 1997 and December 2009 both logged a total of 0.0 mm, meaning no measurable precipitation fell in the entire month. Others, like 1987 and 1988 with 17.8 mm and 13.8 mm respectively, were extremely dry. The contrast between these near-dry months and the 143.4 mm of 1989 illustrates the full range of December conditions at this station. The chart below shows the total monthly precipitation for each year, providing a clear view of how the monthly totals compare.
The chart shows the complete annual series of total monthly precipitation. The table lists the most notable years; the full series comes from Met Office.
| Year | December Total (mm) | Wettest Day (mm) |
|---|---|---|
| 1979 | 94.0 | 28.4 |
| 1985 | 83.8 | 26.7 |
| 1989 | 143.4 | 29.5 |
| 1995 | 91.6 | 28.7 |
| 1997 | 0.0 | 0.0 |
| 2011 | 67.8 | 20.5 |
| 2012 | 104.5 | 22.0 |
The data also reveals that a wet December does not necessarily mean a single intense rainstorm. In 1978, for instance, the monthly total of 132.4 mm was spread across the month with a maximum daily amount of 20.0 mm — a high total built from sustained rainfall rather than one extreme event. By contrast, December 1985 recorded 83.8 mm with a single day contributing 26.7 mm, showing how one storm can dominate a month's figures.
For anyone planning outdoor events in December near London, the record shows that rainfall can be highly unpredictable. The difference between the driest December (0.0 mm in both 1997 and 2009) and the wettest (143.4 mm in 1989) is stark — roughly the difference between a month with no measurable rain at all and a month where rain fell almost every day. The 29.5 mm daily maximum from 14 December 1989 remains the benchmark for a single-day December downpour at this station.
Since the record was set in 1989, no December has come within 11.0 mm of it. The closest attempt was December 1978 at 132.4 mm, and December 2012 reached 104.5 mm — still well short. This record has now stood for over three decades, a testament to how unusual that December was.
Source: Met Office MIDAS data, High Beach station (Essex). Period covered: 1978–2025. All figures are official Met Office measurements.
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© 2026 HistoClima · data: Met Office (OGL v3.0) · not affiliated with Met Office · citation permitted with source.