Hemel Hempstead climate — normals and trends
Hemel Hempstead (United Kingdom) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 9.9 °C and it receives 633 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (16.8 °C on average) and the coldest is January (3.9 °C). Rainfall peaks in May.
Hemel Hempstead averages 38 frost days, 1 hot days (≥ 30 °C) and 127 rainy days per year.
Hemel Hempstead has warmed by +1.8 °C between 1940 and 2025, or +0.21 °C per decade. This trend is statistically significant.
The number of frost days there went from about 53 to 23 per year over the period.
The hottest day of the period reached 37.9 °C (on 19 July 2022) and the coldest -14.1 °C (on 10 February 1986).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
Hemel HempsteadEngland
- coords
- 51.75°, -0.45°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.9°C
Average daily high
13.2°C
Average daily low
6.7°C
Annual rainfall
633mm
Sunshine / day
7.4h
Mean relative humidity
81%
Average peak wind
20.9km/h
Seasonal range
12.9°C
Frost days (< 0 °C)
38 d/yr
Hot days (≥ 30 °C)
1 d/yr
Rainy days (≥ 1 mm)
127 d/yr
Annual snowfall
14.8 cm
Average feels-like high
10.4 °C
Average feels-like low
3.7 °C
Average peak gust
41.2 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
10.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.8 °C
since 1940
+0.2 °C per decade · r² = 0.47 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
37.9 °C
19 July 2022
Coldest day
-14.1 °C
10 February 1986
Wettest day
47 mm
20 June 1973
Windiest day
61.2 km/h
25 January 1990
Strongest gust
125.3 km/h
25 January 1990
Hottest feels-like
37.9 °C
28 July 1947
Coldest feels-like
-18.3 °C
13 December 1981
Snowiest day
15.2 cm
9 January 1968
Sunniest day
16.0 h
30 May 1940
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 6.0 °C | -0.1 °C | 71 mm | +20 mm |
| Feb | 7.3 °C | +0.6 °C | 52 mm | +9 mm |
| Mar | 12.4 °C | +3.1 °C | 15 mm | -33 mm |
| Apr | 16.4 °C | +4.1 °C | 24 mm | -26 mm |
| May | 19.0 °C | +3.4 °C | 22 mm | -36 mm |
| Jun | 23.2 °C | +4.4 °C | 42 mm | -15 mm |
| Jul | 23.6 °C | +2.8 °C | 67 mm | +13 mm |
| Aug | 22.9 °C | +2.5 °C | 28 mm | -29 mm |
| Sep | 18.2 °C | +0.4 °C | 45 mm | -6 mm |
| Oct | 14.2 °C | +0.3 °C | 50 mm | -6 mm |
| Nov | 11.0 °C | +1.6 °C | 110 mm | +53 mm |
| Dec | 9.2 °C | +2.1 °C | 56 mm | +4 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Hemel Hempstead?
Hemel Hempstead has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 9.9 °C and it receives 633 mm of precipitation per year.
What is the hottest day ever recorded in Hemel Hempstead?
The hottest day measured in Hemel Hempstead between 1940 and 2025 was 19 July 2022, reaching 37.9 °C.
What is the coldest day in Hemel Hempstead?
The coldest day measured in Hemel Hempstead between 1940 and 2025 was 10 February 1986, at -14.1 °C.
Does it snow in Hemel Hempstead?
Yes. Hemel Hempstead gets on average 14.8 cm of snow per year and has around 38 frost days.
Has the climate of Hemel Hempstead warmed?
Yes: Hemel Hempstead warmed by +1.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Hemel Hempstead?
The wettest day measured in Hemel Hempstead between 1940 and 2025 was 20 June 1973, with 47 mm of rain in 24 hours.
What was the windiest day in Hemel Hempstead?
The windiest day measured in Hemel Hempstead between 1940 and 2025 was 25 January 1990, with winds reaching 61.2 km/h.
What is the warmest month in Hemel Hempstead?
The warmest month in Hemel Hempstead is July (16.8 °C on average); the coldest is January (3.9 °C).
How much does it rain in Hemel Hempstead?
Hemel Hempstead receives on average 633 mm of precipitation per year, spread over about 127 rainy days.
Is it sunny in Hemel Hempstead?
Hemel Hempstead gets on average 7.4 hours of sunshine per day, roughly 2,701 hours per year over 1940-2025.
What is the biggest single-day snowfall in Hemel Hempstead?
The heaviest 24-hour snowfall measured in Hemel Hempstead between 1940 and 2025 was 9 January 1968, with 15.2 cm.
Are there tropical nights in Hemel Hempstead?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Hemel Hempstead.
What was the most extreme apparent temperature in Hemel Hempstead?
In Hemel Hempstead, between 1940 and 2025, the highest apparent temperature reached 37.9 °C on 28 July 1947, and the lowest was -18.3 °C on 13 December 1981.
Compare Hemel Hempstead with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Hemel Hempstead