Every day for over 100 years, a member of staff at the Botanic Garden has taken manual weather readings of rainfall, air and ground temperature, relative humidity, wind speed and cloud cover at the weather station in the Garden’s Research plots. Meteorological records have been kept at the Garden since 1904.
CUBG’s Met Office daily reader and Assistant Horticulturist, Katie Martyr records the Botanic Garden’s weather readings from the previous 24 hours around 10am each morning in the Garden’s weather recording book, before forwarding the information onto the Met Office digitally.
She collects the weather data from 10:15 the previous day to 10:00am that morning.
Information is recorded in person from observations including a thermometer reading and digital data reading from the weather station (this is cross-referenced with the Beaufort scale (for wind force) and various other specific information tables for wind direction, speed etc).
Data collected consists of:
- Total Cloud
- Wind Direction & Speed
- Present Weather
- Screen dry & wet bulb
- Screen max & min
- Grass min
- Concrete min
- Soil temperature at 10cm, 30cm & 100cm
- State of ground
- Rainfall – daily, monthly & annual total.
A description of the morning and afternoon weather is then noted.
The Met Office maintain the UK’s climate records and these are used to monitor our climate at a national and regional level.
To ensure consistency, weather records are only used from weather observation sites with calibrated, standard instruments and carefully monitored exposure. Although some records have been broken by non-standard stations, these are not accepted as official records.
In 2019, CUBG recorded the highest ever temperature to be recorded in the UK – 38.7 degrees Celsius on Thursday 25 July 2019. This record was broken on 19 July 2022 as provisional figures from the U.K.’s weather service show Coningsby, Lincolnshire, to have recorded 40.3 degrees Celsius.
CUBG’s reading on 19 July was 39.9 degrees Celsius.
Here, Katie tells us more about recent temperature recordings:
What is the hottest temperature we’ve recorded so far this year?
39.9 degrees on 19 July 2022, breaking our previous UK record of 38.7 degrees C, recorded in 2019.
In June we recorded 32.2 degrees on the 17 June 2022. (Santon Downham, in Suffolk, recorded temperatures of 32.7 degrees Celsius on this day, followed by Heathrow Airport and Kew Gardens, which both recorded 32.4C). This was our hottest June on record.
What is the total rainfall so far this year?
This is looking to be the driest year since we started our records.
3.4mm of rain has been recorded for July and 169.8mm for the year so far.
By comparison, our driest year since we started recording was in 1996 when just under 400mm of rain fell.
Cambridge is the driest region of the UK with a 30-year average annual rainfall of just 557mm – which compares with a UK 30-year average annual of around 1150mm which makes CUBG the driest Botanic Garden in the UK.
How have temperatures changed over the last century?
Analysis of the Garden’s weather records show that over the last 100 years our average temperature has risen by 1.2 Celsius and the hottest day, highest monthly and yearly average have all occurred within the last 20 years.
Supporting leading scientific research and welcoming 300,000 visitors a year, Cambridge University Botanic Garden is one of the largest University-owned botanic gardens in the world.
The Garden’s living plant collection of over 8,000 species is spread across 40 acres of landscaped gardens. The collection, which includes iconic and endangered trees and plants, supports University research towards meeting many of the world’s greatest future challenges (such as food security, climate change and medicine).
The Garden also inspires schools, the local community and visitors from around the world about the importance of plants and plant science, horticulture and the joy of gardening.