The mercury rose to 36.4C (97F) at Heathrow and Kew Gardens on August 7 during the heatwave, making it the hottest August day since 2003.
But while much of the UK saw above average mean temperatures in August the Met Office on Tuesday said that more unsettled weather at the start and end of the month balanced the average out.
For the summer as a whole the UK had a mean temperature of 14.75C (58F) – 0.38C above average, according to provisional data from the Met Office.
But across all three months the UK only had 89% of its average summer sunshine at 449.3 hours, with Northern Ireland only seeing 73% (313.9 hours).
The Met Office said: “Despite several notable weather events, neither the month of August nor the summer as a whole for 2020 will be remembered for being particularly prominent from a climatological point of view.
The statistics for August and Summer 2020 are in! 📈
We've had some notable weather events through this summer, from heatwaves ☀️ to named storms 🌬️🌧️
Get all the info on how it compares to long term averages here: https://t.co/2FFQwRGwe5 pic.twitter.com/n1Fbl78WTuAdvertisement— Met Office (@metoffice) September 1, 2020
“Although there was a major summer heatwave in the middle of the month of August for England and Wales, with temperatures reaching 36.4C at Heathrow and Kew Gardens on the 7th, more unsettled and cooler conditions at the start and end of the month balanced the month out.
“Sunshine has been below average in total duration, most notably so for Northern Ireland and Wales.
“Only a handful of counties in the south east of England and north Scotland recorded above average sunshine hours for summer 2020.”
The data also showed that the summer months were wetter than average for the UK with 321mm of rainfall for the three months – 134% of the average.
North west England, south west Scotland and Northern Ireland saw the wettest summer relative to average with around 150% or more of average rainfall.
For the month of August the UK was 1C warmer than the mean temperature at 15.9C (60F) despite the heatwave but only saw 88% of its average sunshine hours at 142.6.
The only region to experience a sunnier than average August was north Scotland with 119% of its average sunshine at 139.7 hours, the Met Office said.
The hot weather also triggered torrential downpours in August that saw 30mm to 60mm falling in just a few hours making up considerable proportions of monthly totals in single shower, it added.
The Met Office said that some regions recorded more than twice the normal monthly rainfall, with Herefordshire recording 226% and Midlothian in Scotland 228% of their average rainfall for the month.
Storms Ellen from August 19 to 21 and Francis on August 25 brought gusts of 46 to 58mph across inland areas and 58 to 70mph across exposed coastal locations, the Met Office said.
Wind speeds reached 79mph at Capel Curig, Wales, during Storm Ellen and 81mph at Needles Old Battery on the Isle of Wight from Storm Francis.
The Met Office said: “The hot spell of weather triggered some torrential downpours that saw 30-60mm falling in just a few hours, making up considerable proportions of monthly totals in single rain events.
“There were two named storms in August in quick succession that brought strong winds and heavy rain to parts of the UK.
“These were two of the most notable August storms in the UK in the last 50 years but were not unprecedented.”
