Updated: 2026-07-31
On 19 July 2022, the thermometer at Cambridge Botanic Garden climbed past 35°C — and it didn't stop. The next day, 20 July 2022, it climbed again. That makes 2 consecutive days above 35°C, the longest heatwave ever recorded at this station. It happened right in the middle of the UK's record-breaking summer of 2022, when the Met Office issued its first ever Red Extreme heat warning. For Cambridge, those two days weren't just hot — they were the most sustained heat this garden has seen since records began. No other summer in the station's entire history has produced a longer stretch of days at or above 35°C.
That's the answer to the question: the longest consecutive run with maximum temperature ≥35°C at Cambridge Botanic Garden lasted 2 days, from 19 July to 20 July 2022.
The Cambridge Botanic Garden weather station (run by the Met Office) has been keeping daily records since 1898. That's over 127 years of data — through the Edwardian era, both World Wars, the heatwaves of 1976 and 1990, and the dramatic warming of the last two decades. Out of all those thousands of daily readings, only a handful have ever reached the 35°C mark. And never, in all that time, has the mercury stayed that high for more than 2 consecutive days. The 2022 heatwave stands alone at the top of the list.
For context: Cambridge is one of the warmest places in the UK, sitting inland in the east of England where summer sun is less tempered by sea breezes. Even so, a day at 35°C is rare. The fact that the longest streak ever is just 2 days tells you how exceptional that July 2022 event was. The previous summers had single-day spikes — 2020, 2019, and 2015 all saw the mercury touch 35°C — but none of them held on for a second day. The 2022 event didn't just break the record; it created a new category of heat for this location.
Here are the five longest streaks of consecutive days with maximum temperature at or above 35°C ever recorded at Cambridge Botanic Garden. The 2022 event is the only one to last more than a single day:
| 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 |
Notice the pattern: before 2022, the record was a single day — and it happened in 2020, 2019, and 2015 separately. The 2022 heatwave doubled the previous record, and it did so during a summer when the UK saw its first ever 40°C reading (recorded elsewhere, but Cambridge felt that same airmass). For a garden that has been measuring heat since 1898, those 2 days in July 2022 were unprecedented.
If you scan the entire series from 1898 to 2025, you'll find that days at or above 35°C are extremely rare at this location. The station's complete daily record covers from 1898-01-02 to 2025-12-31 — that's the full period analysed. In all those years, the longest streak of extreme heat has been exactly 2 days. There have been no longer runs, no multi-day heatwaves above 35°C in the 1970s, the 1980s, or the early 2000s. The 2022 event stands completely alone.
This is the kind of data that matters when you're planning anything outdoors in Cambridge in the summer — a festival, a wedding, a marathon. If you're looking at the forecast and it shows 35°C on consecutive days, you're not just dealing with a warm spell. You're dealing with the kind of heat that this station has only seen once in its entire 127-year history.
For most people, a heatwave in the UK is defined as at least 3 consecutive days above a certain threshold — often 25°C or 28°C. But this record looks at the extreme end: days at or above 35°C. That's the threshold the Met Office considers truly exceptional heat, the kind that poses serious health risks. And at Cambridge Botanic Garden, 35°C is a rare event. The 2-day streak of July 2022 is the station's record for sustained extreme heat, and based on the historical pattern, it could be decades before we see it matched.
So if you ever find yourself in Cambridge on a day when the temperature hits 35°C, take note. You're witnessing something that has only happened a handful of times since Queen Victoria was on the throne. And if it happens two days in a row? You're living through the station's all-time record.
The data from 2020 and 2022 shows a warming trend. Single-day 35°C events occurred in 2015, 2019, and 2020 — three separate occasions in just six years — before the 2-day event of 2022. Compare that to the earlier decades of the record, where 35°C was almost unheard of. While the Met Office's official series for this station doesn't show any longer streaks yet, the recent clustering of extreme heat days is a clear signal. The 2-day record set on 19-20 July 2022 may well be broken in the coming years. But as of the end of 2025, it remains the longest heatwave ever recorded at Cambridge Botanic Garden.
For anyone researching climate change in the UK, this is a clean, unambiguous data point: the extreme heat that used to happen once in a generation is now happening every few years — and the longest streak on record is recent, not historical.
Source: Met Office, MIDAS archive — Cambridge Botanic Garden station, daily maximum temperature records from 1898 to 2025. Data available under Open Government Licence v3.0.
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