Hottest day on record at Cambridge Botanic Garden

Summary of the 1898–2026 period

At the Met Office station in Cambridge Botanic Garden, the thermometer has been read continuously since January 1898. Over these 128 years, the highest temperature ever registered is 39.9°C, reached on 20 July 2022. That date stands as the absolute maximum for the entire series, surpassing the previous peak of 38.7°C recorded on 26 July 2019.

The warmest months on average are July and August, with mean daily maximums of 22.3°C and 22.2°C respectively. The monthly record for July is exactly 39.9°C (the same day as the absolute record), while August shows a monthly record of 36.9°C reached on 11 August 2003. The coldest month is January, with an average maximum of 7.0°C and an average minimum of 1.1°C.

Looking at the yearly breakdown, the hottest individual years in the series are 2022 (max 39.9°C), 2019 (38.7°C), and 2003 (36.9°C). The highest average of daily maximums for a single year is 18.8°C in 2025, compared to a long-term average that remains near 15°C in most recent years. The coldest absolute minimum recorded in the series is -17.2°C, which occurred in 1947.

Average and record maximum temperatures by month

The table below shows for each calendar month the average daily maximum, the maximum temperature ever recorded in that month, and the average daily minimum, all in degrees Celsius.

The two warmest months, July and August, show very similar averages, but July has a much higher extreme: 39.9°C versus 36.9°C in August. The most moderate temperature extremes occur in winter, with January's record max at 15.7°C and December's at 16.0°C, showing that even the warmest winter days stay relatively cool.

The 5 hottest days on record

Here are the five days with the highest maximum temperatures ever recorded at the station, ordered from highest to lowest.

The list clearly shows a concentration of extreme heat in recent decades. Three of the five most extreme days occurred in the 21st century (2003, 2019, 2022), and two of those were just one day apart in July 2022. The 1990 event remains the oldest among the top five, showing how exceptional the recent heatwaves have been.

Maximum temperatures by year

The following table gives, for every year with available data, the highest maximum temperature reached, the average of all daily maximums, and the lowest minimum temperature recorded that year.

The chart shows the complete annual series. The table lists the most notable years; the full series comes from Met Office.

The year 2022 stands out clearly as the hottest in the series, showing the absolute record of 39.9°C and an average maximum of 16.9°C. The 1947 season is notable not only for its high of 33.9°C but for the lowest minimum ever recorded: -17.2°C. Recent years like 2019, 2020, and 2022 have pushed the yearly maximums well above the mid-century levels.

Frequently asked questions

When was the hottest day ever recorded at Cambridge Botanic Garden?

The highest temperature in the entire 1898–2026 record is 39.9°C, registered on 20 July 2022. That day also holds the record for the warmest minimum temperature of 18.9°C, giving a mean temperature of 29.4°C.

What is the average maximum temperature in July and August?

July has an average daily maximum of 22.3°C, making it the hottest month on average. August follows very closely with 22.2°C. Both months share similar average minimums: 11.9°C for July and 11.7°C for August.

Which year had the highest average maximum temperature?

The year 2025 shows the highest annual average of daily maximums at 18.8°C. In comparison, 2022 had an average of 16.9°C, while the 2026 partial data show an average of 13.8°C up to mid-June.

What is the coldest temperature ever recorded at the station?

The lowest minimum temperature is -17.2°C, which occurred in 1947. That year is also known for a harsh winter, with the yearly maximum reaching 33.9°C in summer.

How does the 2003 heatwave compare to the 2022 record?

On 11 August 2003, the temperature reached 36.9°C, which was the record at that time. The 2022 event surpassed it by 3.0°C, with 39.9°C on 20 July, and the following day (19 July 2022) also exceeded the 2003 value at 38.0°C.

Are the recent high temperatures part of a longer trend?

Looking at the yearly maximums, the highest values are concentrated in the 21st century: 2003 (36.9°C), 2006 (35.6°C), 2019 (38.7°C), 2020 (35.1°C), and 2022 (39.9°C). In the entire 20th century, the highest was 36.5°C in 1990, showing a noticeable increase in the most recent decades.