| Measure | Value (anomaly) | Time |
Month cumul. | Record High | Record Low |
| Minimum Temperature |
12.1 °C (+0.0) |
00:04 |
14.0 °C (+1.6) |
18.0 °C (+5.9), 2023 |
8.8 °C (-3.3), 2013 |
| Maximum Temperature |
20.8 °C (+0.8) |
13:20 |
22.3 °C (+1.7) |
30.4 °C (+10.4), 2023 |
16.5 °C (-3.5), 2013 |
| Mean Temperature |
16.4 °C (+0.4) |
|
18.1 °C (+1.7) |
23.4 °C, 2023 |
12.3 °C, 2013 |
| Minimum Humidity |
41% |
12:14 |
51% |
83%, 2016 |
37%, 2015 |
| Maximum Humidity |
86% |
23:54 |
86% |
96%, 2013 |
84%, 2012 |
| Mean Humidity |
69% |
|
70% |
93%, 2016 |
68%, 2020 |
| Minimum Pressure |
1016 hPa |
19:06 |
1015 hPa |
1033 hPa, 2009 |
992 hPa, 2017 |
| Maximum Pressure |
1020 hPa |
00:07 |
1021 hPa |
1038 hPa, 2009 |
1003 hPa, 2017 |
| Mean Pressure |
1018 hPa |
|
1018 hPa |
1036 hPa, 2009 |
999 hPa, 2017 |
| Mean Wind Speed |
4.9 mph (+1.0) |
|
5.1 mph (+1.2) |
9.2 mph, 2012 |
0.6 mph, 2020 |
| Maximum Wind Speed |
14.3 mph |
11:33 |
14.0 mph |
20.0 mph, 2017 |
5.6 mph, 2020 |
| Maximum Gust |
24.2 mph |
11:34 |
23.4 mph |
32.3 mph, 2017 |
10.4 mph, 2020 |
| Mean Wind Direction |
WSW |
|
|
|
|
| Rainfall |
0.8 mm |
|
18.6 mm (112%) |
4.5 mm, 2021 |
|
| Maximum Hourly Rain |
0.8 mm |
23:54 |
|
3.4 mm, 2021 |
|
| Maximum 10-min Rain |
0.6 mm |
23:54 |
|
2.9 mm, 2021 |
|
| Maximum Rain Rate |
1.6 mm/h |
23:54 |
|
30 mm/h, 2021 |
|
| Minimum Dew Point |
6.1 °C |
12:14 |
10.0 °C |
16.5 °C, 2023 |
4.8 °C, 2015 |
| Maximum Dew Point |
13.8 °C |
23:51 |
14.7 °C |
22.2 °C, 2023 |
10.0 °C, 2020 |
| Mean Dew Point |
10.4 °C |
|
12.3 °C |
18.7 °C, 2023 |
8.2 °C, 2009 |
| Measure | Value | Time |
Month cumul. | Record High | Record Low |
| Night Minimum (21-09) |
* 11.8 °C * |
22:58 |
14.5 °C |
18.0 °C, 2023 |
8.8 °C, 2013 |
| Day Maximum (09-21) |
20.8 °C |
13:20 |
22.1 °C |
30.4 °C, 2023 |
16.5 °C, 2013 |
| Max 10m Temp Rise |
0.6 °C |
09:27 |
0.6 °C |
1.0 °C, 2013 |
0.2 °C, 2016 |
| Max 1hr Temp Rise |
2.6 °C |
09:27 |
2.2 °C |
3.6 °C, 2019 |
0.6 °C, 2016 |
| Max 1hr Hum Rise |
10% |
23:50 |
8% |
12%, 2017 |
4%, 2010 |
| Max 10m Temp Fall |
0.5 °C |
13:30 |
0.6 °C |
1.0 °C, 2024 |
0.2 °C, 2010 |
| Max 1hr Temp Fall |
1.1 °C |
03:12 |
1.9 °C |
3.6 °C, 2024 |
0.7 °C, 2010 |
| Max 1hr Hum Fall |
15% |
11:44 |
11% |
19%, 2015 |
3%, 2016 |
| Max 10m Wind Speed |
11.3 mph |
11:42 |
10.3 mph |
14.5 mph, 2017 |
3.1 mph, 2020 |
| Minimum Feels-like |
13.0 °C |
00:01 |
15.7 °C |
22.9 °C, 2023 |
6.0 °C, 2013 |
| Maximum Feels-like |
21.9 °C |
14:51 |
25.3 °C |
39.8 °C, 2023 |
17.0 °C, 2013 |
| Mean Feels-like |
17.9 °C |
|
20.6 °C |
30.0 °C, 2023 |
12.5 °C, 2013 |
| Air-frost Hrs |
0 hrs |
|
0 hrs |
0 hrs, 2009 |
0 hrs, 2009 |
| Minimum PM2.5 |
1 |
23:27 |
1 |
1, 2026 |
0, 2021 |
| Maximum PM2.5 |
9 |
00:12 |
11 |
9, 2026 |
9, 2026 |
| Mean PM2.5 |
4 |
|
4 |
4, 2026 |
4, 2026 |
| Measure | Value (anomaly) |
Month cumul. | Record High | Record Low |
| Temperature Range |
8.7 °C (+0.8) |
8.3 °C (+0.1) |
12.4 °C (+4.5), 2023 |
3.3 °C (-4.6), 2025 |
| Humidity Range |
45% |
35% |
55%, 2015 |
10%, 2016 |
| Pressure Range |
4 hPa |
6 hPa |
12 hPa, 2025 |
2 hPa, 2012 |
| Measure | Value [% of max] |
Month cumul. | Record High | Record Low |
| Sun Hours |
6.4 [54%] | 56 hrs (108%) [46%] |
11 [93%], 2015 |
0 [0%], 2016 |
| Wet Hours |
1 [Mean rain rate: 0.8 mm/h] | 16 hrs (117%) [6.7%] |
7, 2016 |
0, 2009 |
| Cloud Cover |
unknown |
| Events |
None |
| Comments |
data is awaiting quality control from site operator |
| Extra Comments |
|
| Issues |
None known |
| Observer Absent? |
Yes - observations may be unreliable |
| Pond Temperature @ Hampstead Heath |
18.5 °C |