Updated: 2026-07-31
May 15 is the latest spring frost on record at the high-beach station, just 20.8 km from London. That was in 1995, when the thermometer dropped to -0.2 °C on a mid-May night. If you are planning tender planting and want to avoid a late setback, this is the benchmark date that should anchor your calendar.
The point of measurement closest to London is the Met Office station at high-beach, in the county of Essex, sitting at 110 metres above sea level and about 20.8 km from the city. These are its historical records, not a direct measurement of your garden in London. The actual climate in London can differ from this station's readings because of local factors — a different altitude, proximity to the river, or the urban heat island effect that often keeps central London milder at night. That said, this station is the best available reference for the city, and its long series gives us a very good idea of what to expect.
Every spring, gardeners face the same question: when is it safe to put out frost-tender plants like tomatoes, dahlias, or courgettes? The answer is written in the minimum temperatures recorded at high-beach. A frost is defined here as any day when the minimum temperature drops below 0 °C. The last frost of spring is simply the final day in the January-to-June period when the station recorded a sub-zero minimum. Plant after that date, and your odds of avoiding a damaging frost improve dramatically.
The station's absolute minimum temperature record is -10.8 °C, set on 12 January 1987. That is not a spring event — it is a deep winter cold snap, but it shows how far the mercury can fall at this location. It remains the coldest reading in the entire station history, a benchmark that has held since that January night.
The table below shows the last frost date for each year from 1979 through 2025, along with the minimum temperature recorded on that final frosty morning. This is the core data that tells you what you are up against. Notice how the dates swing widely: some years the last frost arrives in March, others it lingers into May.
The chart shows the complete annual series. The table lists the most notable years; the full series comes from Met Office.
| Year | Last Frost Date | Min Temp (°C) |
|---|---|---|
| 1984 | 1984-05-09 | -0.2 |
| 1985 | 1985-04-28 | -0.2 |
| 1996 | 1996-05-04 | -0.1 |
| 2004 | 2004-04-11 | -0.1 |
| 2007 | 2007-03-22 | -3.3 |
| 2020 | 2020-05-12 | -0.1 |
| 2023 | 2023-04-25 | -0.1 |
Look at the spread. In most years, the last frost arrives in April. But there are clear outliers at both ends. The earliest last frost in this series came very early: February 18 in 2002 and February 25 in 2024, both with minimums around -0.5 °C. At the other extreme, May date holders are scattered through the record — you can see them in 1979, 1980, 1981, 1982, 1984, 1995, 1996, 1997, 2011 and 2020. The latest of all was that 15 May 1995. A careful gardener treats mid-May as the safety line: after that date, the station has never again recorded a frost.
Another way to look at risk is the average number of frost days per month. The table below shows how many days each month typically brings a sub-zero minimum at high-beach, averaged across the station's full record. This is the monthly pattern, month by month.
| Month | Average Frost Days |
|---|---|
| January | 10.3 |
| February | 9.5 |
| March | 5.2 |
| April | 2.4 |
| May | 0.3 |
| September | 0.0 |
| October | 0.5 |
| November | 3.9 |
| December | 8.0 |
The monthly averages tell a clear story. January is the frostiest month with an average of 10.3 frost days, and February follows closely at 9.5. By April, the average drops to 2.4 frost days, and by May it is just 0.3. Those May frosts are rare but real — they are the ones that catch out the unwary gardener. The station data shows that a frost in May is possible, with the latest recorded on 15 May 1995. For context, the warmest part of the frost season is far behind by then: the deep cold of winter, when the mercury fell to -10.8 °C on 12 January 1987, is a distant memory.
So, the practical rule for London gardeners, based on the high-beach station record: wait until after mid-May before planting out frost-tender plants. The station has never recorded a frost after 15 May in the entire period from 1978 to 2025. If you want to play it safer, use the 5 May date, which covers the majority of years in the record. And remember: the urban heat of central London may give you a few extra degrees of protection on a cold night, but a late frost can still catch you out, especially in the outer suburbs or toward higher ground.
The data spans from 1 August 1978 to 31 December 2025, giving us nearly five decades of observations at this station. Across that entire history, the coldest temperature ever measured was that -10.8 °C on 12 January 1987 — a record that has stood unmatched for over 38 years. It is a reminder that while these late spring frosts are often mild — many in the table are between -0.1 °C and -0.2 °C — winter can still deliver a serious punch.
For the gardener, the message is reassuring: severe late frosts are rare. The hardest frost recorded in the spring period (January to June) in this series is -3.3 °C, which occurred on 22 March 2007. Frosts that strong in late March can certainly damage early blossoms, but they are not the norm. The typical late spring frost is a light one, just barely below zero, and a fleece or cloche will usually see your plants through.
One more note on the extremes: the 15 May 1995 frost, the latest ever, came with a minimum of just -0.2 °C. In gardening terms, that is a marginal frost — enough to nip the tips of tender plants, but not a deep freeze. Even the worst-case scenario from this record is survivable with a bit of preparation.
Source: Met Office MIDAS data from the high-beach station, Essex, covering August 1978 to December 2025. This page is part of the histoclima.com archive of historical weather records.
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