The 2021 Britain and Ireland heatwaves was a period of unusually hot weather in 2021, with heatwaves in July and September. The July heatwave that led to record-breaking temperatures in the UK and Ireland. Temperatures soared across the United Kingdom over a weekend which saw all four nations record the hottest day of the year. The two heatwaves contributed to the death of more than 1,600 people in England, most of whom were 65 years or over.
Background The Met Office, the UK's national weather and climate service, introduced extreme heatwarnings in June 2021 due to a greatly increased chance of extreme heat events. The warnings are intended to help people and organisations prepare for the health and infrastructure impacts of extreme heat. There were 2,256 excess deaths during summer heatwaves in England in 2021. At that point, it was the highest figure on record.
July heatwave
Events On 17 July, temperatures reached in County Down, Northern Ireland. On 18 July, temperatures reached at Heathrow Airport, London and in Cardiff, Wales. On 19 July, the Met Office issued its first ever extreme heat warning for parts of the UK.
In the Republic of Ireland, Met Éireann issued its first ever Status Orange high temperature warning for six counties on 20 July, after temperatures reached in Athenry, County Galway on 17 July.
On 21 July, temperatures reached at Heathrow, London. In Ireland, temperatures reached at Mount Dillon, County Roscommon. In Northern Ireland a new record for maximum temperature was set, with was reached at Castlederg, County Tyrone.
Despite the extreme weather warning, the 2021 July heatwave was relatively mild in comparison to heatwaves in the UK and Ireland of previous and subsequent years, with heatwaves in previous years surpassing the maximum temperature of this heatwave, particularly in the south east.
Impact
Health The heatwave contributed to the death of more than 900 people in England, most of whom were 65 years or over. The Welsh Ambulance Service experienced a 30% increase in the number of calls for life-threatening incidents.
Infrastructure The surface of roads including the A396 and B3224 melted during the heatwave. In London, the mayor launched a network to help the public find areas to find free access to cool spaces. The scheme continued running in later years.
Environmental Thousands of fish in a pool in Somerset died during the heatwave; it was thought that the heat caused low levels of oxygen in the water.
September heatwave
The September heatwave broke the record for consecutive days in September with the temperature reaching or above. The night of 7 to 8 September saw Wales break a 72-year-old record for the warmest September night: Aberporth on the Ceredigion Coast Path recorded an overnight low of .
Impact
Health The heatwave contributed to the death of more than 700 people in England, most of whom were 65 years or over.
See also
References