| Measure | Value (anomaly) | Time |
Month cumul. | Record High | Record Low |
| Minimum Temperature |
12.2 °C (-0.3) |
06:45 |
14.9 °C (+2.3) |
16.1 °C (+3.6), 2022 |
7.7 °C (-4.8), 2015 |
| Maximum Temperature |
23.2 °C (+2.3) |
16:40 |
22.6 °C (+1.6) |
28.7 °C (+7.8), 2023 |
14.8 °C (-6.1), 2015 |
| Mean Temperature |
17.2 °C (+1.0) |
|
18.9 °C (+1.9) |
21.5 °C, 2023 |
11.9 °C, 2015 |
| Minimum Humidity |
42% |
16:45 |
53% |
85%, 2024 |
40%, 2013 |
| Maximum Humidity |
87% |
06:52 |
86% |
97%, 2013 |
77%, 2012 |
| Mean Humidity |
66% |
|
71% |
92%, 2024 |
58%, 2012 |
| Minimum Pressure |
1020 hPa |
00:05 |
1017 hPa |
1024 hPa, 2012 |
1008 hPa, 2011 |
| Maximum Pressure |
1027 hPa |
23:51 |
1022 hPa |
1030 hPa, 2012 |
1015 hPa, 2011 |
| Mean Pressure |
1024 hPa |
|
1020 hPa |
1027 hPa, 2012 |
1011 hPa, 2013 |
| Mean Wind Speed |
3.6 mph (-0.3) |
|
6.1 mph (+2.2) |
8.0 mph, 2011 |
1.4 mph, 2021 |
| Maximum Wind Speed |
10.7 mph |
01:20 |
15.3 mph |
20.7 mph, 2011 |
6.7 mph, 2014 |
| Maximum Gust |
32.3 mph |
01:12 |
27.2 mph |
32.3 mph, 2026 |
8.7 mph, 2014 |
| Mean Wind Direction |
WNW |
|
|
|
|
| Rainfall |
0.0 mm |
|
2.0 mm (24%) |
7.2 mm, 2022 |
|
| Maximum Hourly Rain |
n/a |
|
|
5, 2022 |
|
| Maximum 10-min Rain |
n/a |
|
|
3.1, 2024 |
|
| Maximum Rain Rate |
n/a |
|
|
48, 2024 |
|
| Minimum Dew Point |
9.1 °C |
21:08 |
11.3 °C |
14.1 °C, 2022 |
4.1 °C, 2019 |
| Maximum Dew Point |
11.9 °C |
10:49 |
15.4 °C |
19.8 °C, 2016 |
8.7 °C, 2012 |
| Mean Dew Point |
10.3 °C |
|
13.2 °C |
16.4 °C, 2016 |
7.0 °C, 2012 |
| Measure | Value | Time |
Month cumul. | Record High | Record Low |
| Night Minimum (21-09) |
12.2 °C |
06:41 |
15.7 °C |
16.1 °C, 2022 |
9.3 °C, 2015 |
| Day Maximum (09-21) |
23.2 °C |
16:41 |
22.5 °C |
28.7 °C, 2023 |
14.8 °C, 2015 |
| Max 10m Temp Rise |
0.7 °C |
12:39 |
0.6 °C |
1.3 °C, 2009 |
0.4 °C, 2014 |
| Max 1hr Temp Rise |
2.7 °C |
09:07 |
2.1 °C |
3.7 °C, 2013 |
1.0 °C, 2015 |
| Max 1hr Hum Rise |
10% |
20:05 |
8% |
15%, 2011 |
6%, 2012 |
| Max 10m Temp Fall |
0.7 °C |
19:57 |
0.7 °C |
1.2 °C, 2009 |
0.3 °C, 2010 |
| Max 1hr Temp Fall |
3.3 °C |
20:08 |
1.9 °C |
3.3 °C, 2026 |
0.8 °C, 2010 |
| Max 1hr Hum Fall |
10% |
09:02 |
11% |
17%, 2013 |
5%, 2016 |
| Max 10m Wind Speed |
7.6 mph |
12:43 |
11.3 mph |
13.3 mph, 2011 |
4.3 mph, 2021 |
| Minimum Feels-like |
13.4 °C |
06:27 |
17.1 °C |
19.9 °C, 2022 |
7.7 °C, 2015 |
| Maximum Feels-like |
24.6 °C |
16:38 |
26.3 °C |
35.2 °C, 2023 |
16.3 °C, 2015 |
| Mean Feels-like |
18.6 °C |
|
21.9 °C |
26.3 °C, 2023 |
12.6 °C, 2015 |
| Air-frost Hrs |
0 hrs |
|
0 hrs |
0 hrs, 2009 |
0 hrs, 2009 |
| Minimum PM2.5 |
1 |
12:45 |
1 |
1, 2026 |
0, 2021 |
| Maximum PM2.5 |
11 |
21:10 |
10 |
11, 2026 |
11, 2026 |
| Mean PM2.5 |
4 |
|
3 |
4, 2026 |
4, 2026 |
| Measure | Value (anomaly) |
Month cumul. | Record High | Record Low |
| Temperature Range |
11.0 °C (+2.6) |
7.7 °C (-0.7) |
13.4 °C (+5.0), 2023 |
6.0 °C (-2.4), 2010 |
| Humidity Range |
45% |
33% |
57%, 2013 |
12%, 2024 |
| Pressure Range |
6 hPa |
5 hPa |
11 hPa, 2015 |
2 hPa, 2014 |
| Measure | Value [% of max] |
Month cumul. | Record High | Record Low |
| Sun Hours |
12 [99%] | 24 hrs (90%) [39%] |
12 [99%], 2012 |
0 [0%], 2016 |
| Wet Hours |
0 | 2 hrs (29%) [1.7%] |
7, 2016 |
0, 2009 |
| Cloud Cover |
unknown |
| Events |
Maximum possible sunshine |
| 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 |
19.0 °C |