Like the rest of the United Kingdom, the climate in Sheffield is generally temperate. The Pennines to the west of the city can create a cool, gloomy and wet environment, but they also provide shelter from the prevailing westerly winds, casting a “rain shadow” across the area. Between 1971 and 2000 Sheffield averaged 824.7 millimetres (32.47 in) of rain per year; December was the wettest month with 91.9 millimetres (3.62 in) and July the driest with 51.0 millimetres (2.01 in). July was also the hottest month, with an average maximum temperature of 20.8 °C (69.4 °F). The highest temperature ever recorded in the city of Sheffield was 35.6 °C (96.1 °F), on 25 July 2019. The average minimum temperature in January and February was 1.6 °C (34.9 °F), though the lowest temperatures recorded in these months can be between −10 and −15 °C (14 and 5 °F), although since 1960, the temperature has never fallen below −9.2 °C (15.4 °F), suggesting that urbanisation around the Weston Park site during the second half of the 20th century may prevent temperatures below −10 °C (14 °F) occurring.
The coldest temperature to be recorded was −8.2 °C (17.2 °F) in 2010. (Note: The official Weston Park Weather Station statistics, which can also be viewed at Sheffield Central Library, has the temperature at −8.7 °C (16.3 °F), recorded on 20 December, and states that to be the lowest December temperature since 1981.) The coldest temperature ever recorded in the city of Sheffield at Weston Park, since records began in 1882, is −14.6 °C (5.7 °F), registered in February 1895. The lowest daytime maximum temperature in the city since records began is −5.6 °C (21.9 °F), also recorded in February 1895. More recently, −4.4 °C (24.1 °F) was recorded as a daytime maximum at Weston Park, on 20 December 2010 (from the Weston Park Weather Station statistics, which also can be viewed at Sheffield Central Library.) On average, through the winter months of December to March, there are 67 days during which ground frost occurs.