The Central England Temperature (CET) is the longest-running instrumental temperature record in the world, starting in 1659. The Mean CET for any month is calculated by averaging the high and low temperatures for each day of that month at three weather stations in central England: Stonyhurst (Lancashire), Rothamsted (Hertfordshire), and Pershore (Worcestershire). It is recorded in degrees Celsius.

Some statistics for August:

HOTTEST:

19.1 -- 1995

19.0 -- 1997

18.7 -- 2022

18.6 -- 1947, 1975

COLDEST:

12.9 -- 1912

13.0 -- 1694, 1695

13.3 -- 1725

13.5 -- 1674, 1683, 1844, 1845, 1956

AVERAGES:

1971-2000: 16.24

1981-2010: 16.45

1991-2020: 16.61

2001-2023: 16.64

LAST TIME UNDER X DEGREES:

16 -- 15.7, 2017

15 -- 14.6, 1993

14 -- 13.7, 1986

13 -- 12.9, 1912

DATA FROM:

https://www.metoffice.gov.uk/hadobs/hadcet/cet_info_mean.html

EDIT: As of July 19, 2024, CET v2.1.0.0 has been released, superseding v2.0.1.0. Historic data is from v2.0.1.0, but this question will resolve based on v2.1.0.0 data.