Updated: 2026-08-02
2 days — that's the longest heatwave ever recorded at Cambridge Botanic Garden, defined as consecutive days with a maximum temperature reaching at least 35°C. It happened on 19–20 July 2022, during one of the most intense heat episodes the UK has seen. That short, sharp burst of extreme heat remains unbeaten in more than 12 decades of records.
The numbers are stark. At Cambridge Botanic Garden, the Met Office station has been taking daily readings since 1898, giving us more than 127 years of continuous observations. Yet in all that time, only one event has managed to string together two consecutive days with maxima of 35°C or higher: the heatwave of 19–20 July 2022. That single 2-day stretch stands alone at the top of the record books.
To put it in perspective — and this matters — the threshold itself is the story. A day at 35°C is rare in Britain; Cambridge, sitting inland in the east of England, is one of the warmest spots in the country, but even here the climate has only occasionally delivered such heat. The fact that the longest heatwave on record is just 2 days tells you how unusual it is for the UK to sustain that kind of tropical heat. The record was set in 2022, and it is a recent one, not something from a distant, forgotten summer.
Below are the five longest streaks of consecutive days with maximum temperatures at or above 35°C at Cambridge Botanic Garden, ranked from longest to shortest. Note how the 2022 event leads with 2 days; every other event on this list lasted a single day. These are the top 5 in the entire series from 1898 to 2025.
| Start date | End date | Consecutive days |
|---|---|---|
| 2022-07-19 | 2022-07-20 | 2 |
| 2020-08-13 | 2020-08-13 | 1 |
| 2020-08-08 | 2020-08-08 | 1 |
| 2019-07-26 | 2019-07-26 | 1 |
| 2015-07-02 | 2015-07-02 | 1 |
What jumps out is the recency of these events. Four of the five longest heatwaves have occurred since 2015, and the top two belong to the summers of 2022 and 2020. The 2022 event stands alone in its class — the only one to last more than a single day. The absence of older, longer heatwaves in this ranking is a striking feature of the Cambridge record: the city simply did not experience multi-day stretches of 35°C heat in the earlier decades of the 20th century, at least not according to the daily observations from this station.
The definition used throughout this page is a practical one: a heatwave is a run of consecutive days where the daily maximum temperature reaches 35°C or higher at Cambridge Botanic Garden. This is a high bar — it's the kind of warmth usually associated with Mediterranean summers, not the UK. That's why the record is measured in days, not weeks. A single day at 35°C is itself exceptional here; to get two in a row, as happened in July 2022, required a very particular set of atmospheric conditions.
For comparison, consider what didn't make the list. The top 5 shows only those events with the longest streaks, but there are other days on record that hit 35°C; they simply didn't form part of a longer sequence. The table above captures the five most significant runs — and the 2022 event is the only one to exceed a single day.
The 19–20 July 2022 heatwave is not just the longest on record; it's also the most recent, which means it's a symptom of the warming trend seen across the UK in recent decades. The fact that no earlier heatwave in the 1898–2025 series reached 2 days is remarkable. Even in the notable hot summers of 1976, 1990 or 2003 — famous for prolonged warmth — Cambridge Botanic Garden did not record two consecutive days at this extreme threshold.
That said, this is a narrow measure. It's possible that a longer heatwave occurred at temperatures below 35°C (say, at 32°C or 33°C), but that would be a different definition. Under the strict 35°C threshold used here, the answer is unambiguous: the longest heatwave ever at this station lasted 2 days, and it happened on 19–20 July 2022.
The records run from 1898 to 2025, with data collected at the Cambridge Botanic Garden station itself. This is a long and consistent series, one of the most reliable in the UK, and it gives us confidence in the conclusions above. When we say "ever," we mean from the start of these daily observations in 1898 through to the end of 2025 — more than a century of data, and the 2022 event still holds the top spot.
If you're planning an outdoor event, a wedding, or a trip to Cambridge in summer, the lesson from this record is clear: extreme heat here tends to be short-lived. But when it arrives, as in July 2022, it can be intense enough to break a record that had stood for the entire history of the station.
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