| Measure | Value (anomaly) | Time |
Month cumul. | Record High | Record Low |
| Minimum Temperature |
17.1 °C (+6.9) |
23:05 |
13.4 °C (+2.0) |
17.1 °C (+6.9), 2026 |
5.8 °C (-4.4), 2012 |
| Maximum Temperature |
23.5 °C (+6.6) |
15:25 |
22.3 °C (+3.3) |
27.4 °C (+10.5), 2011 |
15.4 °C (-1.5), 2018 |
| Mean Temperature |
20.9 °C (+6.7) |
|
17.9 °C (+2.6) |
20.9 °C, 2026 |
11.6 °C, 2018 |
| Minimum Humidity |
48% |
16:15 |
53% |
83%, 2024 |
37%, 2015 |
| Maximum Humidity |
83% |
11:47 |
87% |
98%, 2010 |
81%, 2016 |
| Mean Humidity |
69% |
|
72% |
91%, 2024 |
68%, 2015 |
| Minimum Pressure |
1010 hPa |
05:29 |
1017 hPa |
1031 hPa, 2015 |
999 hPa, 2022 |
| Maximum Pressure |
1016 hPa |
23:48 |
1023 hPa |
1034 hPa, 2015 |
1009 hPa, 2013 |
| Mean Pressure |
1013 hPa |
|
1020 hPa |
1032 hPa, 2015 |
1003 hPa, 2024 |
| Mean Wind Speed |
5.1 mph (+1.2) |
|
4.3 mph (+0.4) |
8.3 mph, 2024 |
0.8 mph, 2025 |
| Maximum Wind Speed |
14.1 mph |
15:55 |
12.5 mph |
18.8 mph, 2024 |
7.6 mph, 2009 |
| Maximum Gust |
20.7 mph |
09:41 |
20.4 mph |
32.3 mph, 2024 |
10.5 mph, 2009 |
| Mean Wind Direction |
SW |
|
|
|
|
| Rainfall |
0.6 mm |
|
26.8 mm (54%) |
12.5 mm, 2022 |
|
| Maximum Hourly Rain |
0.4 mm |
11:33 |
|
4.8 mm, 2022 |
|
| Maximum 10-min Rain |
0.4 mm |
11:33 |
|
1.5 mm, 2024 |
|
| Maximum Rain Rate |
n/a |
|
|
30, 2024 |
|
| Minimum Dew Point |
10.7 °C |
19:57 |
9.6 °C |
12.0 °C, 2014 |
2.5 °C, 2015 |
| Maximum Dew Point |
17.9 °C |
11:11 |
15.1 °C |
17.9 °C, 2026 |
8.8 °C, 2018 |
| Mean Dew Point |
14.8 °C |
|
12.4 °C |
14.8 °C, 2026 |
6.7 °C, 2018 |
| Measure | Value | Time |
Month cumul. | Record High | Record Low |
| Night Minimum (21-09) |
* 20.3 °C * |
06:22 |
14.0 °C |
20.3 °C, 2026 |
5.8 °C, 2012 |
| Day Maximum (09-21) |
23.5 °C |
15:25 |
22.2 °C |
27.4 °C, 2011 |
15.4 °C, 2018 |
| Max 10m Temp Rise |
0.5 °C |
12:16 |
0.7 °C |
0.9 °C, 2025 |
0.3 °C, 2024 |
| Max 1hr Temp Rise |
2.0 °C |
12:38 |
2.4 °C |
4.4 °C, 2025 |
0.7 °C, 2024 |
| Max 1hr Hum Rise |
7% |
18:03 |
8% |
14%, 2022 |
3%, 2024 |
| Max 10m Temp Fall |
0.5 °C |
11:36 |
0.5 °C |
0.7 °C, 2025 |
0.2 °C, 2021 |
| Max 1hr Temp Fall |
1.4 °C |
22:31 |
1.8 °C |
3.3 °C, 2025 |
0.7 °C, 2021 |
| Max 1hr Hum Fall |
17% |
13:53 |
11% |
17%, 2015 |
6%, 2019 |
| Max 10m Wind Speed |
10.2 mph |
15:43 |
9.1 mph |
14.3 mph, 2016 |
5.7 mph, 2025 |
| Minimum Feels-like |
19.3 °C |
23:05 |
14.9 °C |
19.3 °C, 2026 |
3.8 °C, 2012 |
| Maximum Feels-like |
27.9 °C |
12:31 |
25.5 °C |
30.2 °C, 2011 |
16.1 °C, 2018 |
| Mean Feels-like |
24.9 °C |
|
20.5 °C |
24.9 °C, 2026 |
11.7 °C, 2018 |
| Air-frost Hrs |
0 hrs |
|
0 hrs |
0 hrs, 2009 |
0 hrs, 2009 |
| Minimum PM2.5 |
1 |
14:50 |
1 |
1, 2026 |
0, 2021 |
| Maximum PM2.5 |
20 |
00:01 |
15 |
20, 2026 |
20, 2026 |
| Mean PM2.5 |
6 |
|
5 |
6, 2026 |
6, 2026 |
| Measure | Value (anomaly) |
Month cumul. | Record High | Record Low |
| Temperature Range |
6.4 °C (-0.3) |
8.8 °C (+1.4) |
13.9 °C (+7.2), 2011 |
4.5 °C (-2.2), 2009 |
| Humidity Range |
35% |
33% |
55%, 2011 |
14%, 2009 |
| Pressure Range |
6 hPa |
6 hPa |
14 hPa, 2020 |
2 hPa, 2011 |
| Measure | Value [% of max] |
Month cumul. | Record High | Record Low |
| Sun Hours |
6.8 [64%] | 178 hrs (121%) [52%] |
10.6 [100%], 2011 |
0 [0%], 2022 |
| Wet Hours |
2
[Mean rain rate: 0.3 mm/h] | 28 hrs (68%) [3.9%] |
9, 2024 |
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 |
17.0 °C |
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