Measure | Value (anomaly) | Time |
Month cumul. | Record High | Record Low |
Minimum Temperature |
12.0 °C (+3.4) |
06:15 |
9.6 °C (+1.6) |
12.6 °C (+4.0), 2017 |
1.0 °C (-7.6), 2010 |
Maximum Temperature |
13.4 °C (-4.0) |
16:07 |
19.6 °C (+2.7) |
25.5 °C (+8.1), 2024 |
11.4 °C (-6.0), 2010 |
Mean Temperature |
17.8 °C (-0.3) |
|
15.3 °C (+2.2) |
19.2 °C, 2024 |
6.9 °C, 2010 |
Minimum Humidity |
44% |
15:27 |
43% |
79%, 2023 |
34%, 2009 |
Maximum Humidity |
94% |
02:36 |
81% |
94%, 2016 |
74%, 2009 |
Mean Humidity |
74% |
|
61% |
89%, 2023 |
52%, 2015 |
Minimum Pressure |
1001 hPa |
17:55 |
1011 hPa |
1033 hPa, 2012 |
993 hPa, 2017 |
Maximum Pressure |
1005 hPa |
23:47 |
1016 hPa |
1040 hPa, 2019 |
1002 hPa, 2017 |
Mean Pressure |
1003 hPa |
|
1013 hPa |
1036 hPa, 2019 |
996 hPa, 2017 |
Mean Wind Speed |
5.7 mph (+1.0) |
|
3.6 mph (-1.1) |
7.1 mph, 2015 |
1.9 mph, 2020 |
Maximum Wind Speed |
13.4 mph |
16:31 |
11.5 mph |
17.8 mph, 2015 |
7.6 mph, 2010 |
Maximum Gust |
18.9 mph |
11:31 |
17.4 mph |
27.5 mph, 2015 |
10.9 mph, 2010 |
Mean Wind Direction |
NNE |
|
|
|
|
Rainfall |
0.0 mm |
|
25.1 mm (141%) |
27.8 mm, 2025 |
|
Maximum Hourly Rain |
n/a |
|
|
26.4, 2025 |
|
Maximum 10-min Rain |
n/a |
|
|
10.6, 2025 |
|
Maximum Rain Rate |
n/a |
|
|
96, 2025 |
|
Minimum Dew Point |
10.4 °C |
23:38 |
3.5 °C |
10.4 °C, 2016 |
-2.2 °C, 2010 |
Maximum Dew Point |
14.9 °C |
12:06 |
10.2 °C |
16.1 °C, 2024 |
2.8 °C, 2010 |
Mean Dew Point |
12.6 °C |
|
6.9 °C |
12.8 °C, 2024 |
0.1 °C, 2010 |
Measure | Value | Time |
Month cumul. | Record High | Record Low |
Night Minimum (21-09) |
* 12.4 °C * |
06:15 |
9.7 °C |
14.0 °C, 2025 |
1.0 °C, 2010 |
Day Maximum (09-21) |
* 23.8 °C * |
16:07 |
20.5 °C |
25.5 °C, 2024 |
11.4 °C, 2010 |
Max 10m Temp Rise |
0.6 °C |
11:26 |
0.7 °C |
0.9 °C, 2019 |
0.4 °C, 2018 |
Max 1hr Temp Rise |
2.3 °C |
12:14 |
2.9 °C |
4.5 °C, 2019 |
1.1 °C, 2018 |
Max 1hr Hum Rise |
18% |
21:00 |
8% |
30%, 2025 |
6%, 2009 |
Max 10m Temp Fall |
0.8 °C |
20:45 |
0.5 °C |
2.0 °C, 2025 |
0.4 °C, 2009 |
Max 1hr Temp Fall |
3.1 °C |
21:10 |
1.9 °C |
6.5 °C, 2025 |
1.3 °C, 2018 |
Max 1hr Hum Fall |
13% |
12:15 |
12% |
22%, 2019 |
6%, 2023 |
Max 10m Wind Speed |
10.0 mph |
16:21 |
8.9 mph |
14.9 mph, 2015 |
5.4 mph, 2020 |
Minimum Feels-like |
14.1 °C |
23:52 |
9.6 °C |
14.5 °C, 2025 |
-1.0 °C, 2010 |
Maximum Feels-like |
26.5 °C |
16:26 |
21.7 °C |
29.4 °C, 2024 |
11.4 °C, 2010 |
Mean Feels-like |
20.4 °C |
|
16.2 °C |
22.0 °C, 2024 |
6.0 °C, 2010 |
Air-frost Hrs |
0 hrs |
|
0 hrs |
0 hrs, 2009 |
0 hrs, 2009 |
Measure | Value (anomaly) |
Month cumul. | Record High | Record Low |
Temperature Range |
1.4 °C (-7.4) |
10.0 °C (+1.1) |
14.1 °C (+5.3), 2020 |
1.4 °C (-7.4), 2016 |
Humidity Range |
50% |
38% |
58%, 2019 |
15%, 2023 |
Pressure Range |
4 hPa |
5 hPa |
9 hPa, 2019 |
2 hPa, 2018 |
Measure | Value [% of max] |
Month cumul. | Record High | Record Low |
Sun Hours |
12 [86%] | 96 hrs (135%) [58%] |
12 [86%], 2016 |
0.2 [1%], 2018 |
Wet Hours |
0 | 22 hrs (142%) [7.6%] |
8, 2018 |
0, 2009 |
Cloud Cover |
am: Hazy transitioned to Sunny pm: Mostly Sunny |
Events |
None |
Comments |
- |
Extra Comments |
|
Issues |
T/H data from casa; Wind data from Harpenden |
Observer Absent? |
Yes - observations may be unreliable |
Pond Temperature @ Hampstead Heath |
0.0 °C |