Updated: 2026-07-29
In 2024, the thermometer at Cambridge Botanic Garden dropped below 0 °C on just 11 days — the lowest number ever recorded in the 127-year series that runs from 1911 through 2024. That is fewer frosts than any year since the First World War, and it sits far below the long-term pattern. At the other extreme, 1917 stands as the frostiest year on record, with 90 freezing nights — more than eight times the 2024 count. The gap between those two years illustrates how much the frost climate of Cambridge has shifted.
The Met Office defines a frost day as any 24-hour period in which the minimum temperature (tmin) falls below 0 °C. At Cambridge Botanic Garden the station has been observing continuously since the earliest complete year of 1911. The data that follows comes directly from the UK Met Office MIDAS archive and covers every year from 1911 to 2024, with a total of 114 calendar years of observations.
2024 delivered only 11 frost days. That is the absolute minimum in the entire series, beating the previous low of 20 set in 2011. To give that number some perspective: 1917 produced 90 frost days, and even in the relatively mild 2000s the mean annual count hovered around 40–50. The year 2024 also had the highest mean minimum temperature of any year in the record: the annual tmin average was 7.7 °C, the warmest value in the series. That combination — fewest frosts and mildest nights — makes 2024 an outlier that stands apart even from recent warm years such as 2023 (33 frost days, tmin average 7.6 °C).
The ten-year period centred on the First World War was brutally cold by modern standards. The standout year is 1917 with 90 frost days, but 1919 came close with 86, and 1929 also recorded 86. In contrast, the decade from 2015 to 2024 averaged roughly 35 frost days per year. The coldest mean minimum temperature on record belongs to 1919, when the annual tmin average dropped to 3.8 °C — a full 3.9 °C below the 2024 figure.
The table below shows the five years with the lowest mean minimum temperature (the coldest nights) and the five years with the highest mean minimum temperature (the mildest nights). These values come from the same station and the same period; they help explain why frost days vary so much from one year to the next.
| Ranking | Year | Mean minimum temperature (°C) |
|---|---|---|
| Coldest | 1919 | 3.8 |
| Coldest | 1962 | 4.4 |
| Coldest | 1940 | 4.5 |
| Coldest | 1963 | 4.6 |
| Coldest | 1917 | 4.7 |
| Warmest | 2024 | 7.7 |
| Warmest | 2023 | 7.6 |
| Warmest | 2006 | 7.5 |
| Warmest | 2014 | 7.5 |
| Warmest | 2022 | 7.4 |
The full annual series is shown below. Each year lists the number of days with tmin below 0 °C. The data reveal a gradual decline in frost frequency over the past century, though with large annual swings driven by individual cold winters such as 1947 (79 frost days), 1963 (81), and 2010 (76).
The chart shows the complete annual series. The table lists the most notable years; the full series comes from Met Office.
| Year | Frost days |
|---|---|
| 1917 | 90 |
| 1919 | 86 |
| 1929 | 86 |
| 1940 | 81 |
| 1947 | 79 |
| 1963 | 81 |
| 2024 | 11 |
In recent decades the number of frost days has stayed well below the historical peaks. The 1990s and 2000s saw several years with fewer than 30 frosts: 1990 (22), 2002 (31), 2011 (20), 2014 (23), and 2024 (11). Meanwhile the coldest winters of the 20th century — 1917 with 90 frost days and 1919 and 1929 with 86 each — remain untouched. The 90-frost-day record from 1917 has stood for more than a century and still looks secure.
For gardeners and growers in Cambridge, the frost-day count is a practical measure of the growing season length. A year with 11 frost days, as in 2024, means fewer late-spring or early-autumn freezes; a year with 90 frost days, as in 1917, means a short, cold window for tender plants. The long-term trend towards fewer frosts reflects the warming minimum temperatures observed across southern England.
Source: Met Office MIDAS (Integrated Data Archive System), Cambridge Botanic Garden station (ID 00454). Data for 1911–2024, covering 114 complete years. Official data under Open Government Licence v3.0, held at CEDA (Centre for Environmental Data Analysis).
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© 2026 HistoClima · data: Met Office (OGL v3.0) · not affiliated with Met Office · citation permitted with source.