Heatwaves in Reading

Definition of a heatwave

In Reading and the surrounding area, the official definition of a heatwave is a spell of three days or more, each of which has a maximum temperature of 28 °C or above.

Occurrences since 1970

The University's weather station was moved to its current location in January 1970. Between 1970 and 2026 heatwaves have occurred on 45 occasions between May and September.

Month:	May	June	July	August	September	Total
No. of heatwaves that began in the month:	1	10	23	10	1	45
No. of heatwave days in the month:	6	40	113	60	6	225

Highest temperature each month in a heatwave:
33.0 °C (May 2026)
34.9 °C (June 2026)
37.6 °C (July 2022)
36.4 °C (August 2003)
31.4 °C (September 2023)

Some statistics:

Earliest day forming part of a heatwave:
23 May 2026
Latest day that was part of a heatwave:
9 September 2023
Most heatwave days in a year:
25 (2026)
Longest heatwave: 16 days
23 June - 8 July 1976
Most heatwaves in a year:
4 (in 1995, 2018 and 2026)
Fewest heatwaves in a year
0 (in each of 1971-1972, 1974, 1977-1982, 1984-1985, 1987-1988, 1991-1994, 1996-1998, 2000, 2002, 2004-2005, 2010-2012 and 2014-2015)

Both graphs updated to 17 July 2026

Each year in the 11-year period 2016-2026 experienced a heatwave; previously heatwaves had never occurred in more than two consecutive years, namely 1975-1976 and in 1989-1990.

In the 57-year period 1970-2026 heatwaves occurred in 26 of the years, 16 of them since 2000. The period 2001-2026 saw 147 of the 225 heatwave days recorded since 1970.