Measure | Value (anomaly) | Time |
Month cumul. | Record High | Record Low |
Minimum Temperature |
4.1 °C (+0.7) |
07:09 |
4.3 °C (+0.8) |
8.2 °C (+4.8), 2019 |
-1.8 °C (-5.2), 2018 |
Maximum Temperature |
8.5 °C (-1.1) |
00:04 |
10.6 °C (+0.9) |
14.0 °C (+4.4), 2019 |
-0.1 °C (-9.7), 2018 |
Mean Temperature |
5.6 °C (-0.2) |
|
7.1 °C (+0.9) |
10.8 °C, 2019 |
-1.3 °C, 2018 |
Minimum Humidity |
55% |
15:04 |
60% |
85%, 2022 |
34%, 2017 |
Maximum Humidity |
82% |
11:47 |
87% |
97%, 2012 |
71%, 2017 |
Mean Humidity |
73% |
|
78% |
90%, 2022 |
55%, 2017 |
Minimum Pressure |
993 hPa |
13:07 |
998 hPa |
1035 hPa, 2011 |
982 hPa, 2014 |
Maximum Pressure |
1003 hPa |
00:00 |
1014 hPa |
1038 hPa, 2011 |
995 hPa, 2018 |
Mean Pressure |
999 hPa |
|
1005 hPa |
1036 hPa, 2011 |
991 hPa, 2020 |
Mean Wind Speed |
7.5 mph (+2.3) |
|
8.2 mph (+3.0) |
11.1 mph, 2018 |
1.6 mph, 2021 |
Maximum Wind Speed |
7.5 mph |
00:00 |
11.2 mph |
22.0 mph, 2018 |
7.1 mph, 2010 |
Maximum Gust |
15.7 mph |
00:00 |
18.9 mph |
37.0 mph, 2009 |
9.0 mph, 2010 |
Mean Wind Direction |
WNW |
|
|
|
|
Rainfall |
1.7 mm |
|
7.4 mm (294%) |
8.6 mm, 2014 |
|
Maximum Hourly Rain |
0.7 mm |
02:07 |
|
3.1 mm, 2014 |
|
Maximum 10-min Rain |
0.7 mm |
02:07 |
|
1.0 mm, 2024 |
|
Maximum Rain Rate |
11 mm/h |
02:07 |
|
18 mm/h, 2020 |
|
Minimum Dew Point |
-1.8 °C |
14:43 |
-1.5 °C |
5.5 °C, 2019 |
-6.0 °C, 2015 |
Maximum Dew Point |
4.5 °C |
00:00 |
7.6 °C |
9.8 °C, 2019 |
-1.2 °C, 2013 |
Mean Dew Point |
1.1 °C |
|
3.4 °C |
7.9 °C, 2019 |
-3.5 °C, 2018 |
Measure | Value | Time |
Month cumul. | Record High | Record Low |
Night Minimum (21-09) |
4.1 °C |
07:09 |
4.3 °C |
8.0 °C, 2019 |
-1.7 °C, 2018 |
Day Maximum (09-21) |
* 6.7 °C * |
15:01 |
9.7 °C |
14.0 °C, 2019 |
-0.6 °C, 2018 |
Max 10m Temp Rise |
0.4 °C |
09:31 |
0.4 °C |
0.7 °C, 2010 |
0.2 °C, 2013 |
Max 1hr Temp Rise |
1.6 °C |
14:45 |
1.5 °C |
2.7 °C, 2010 |
0.6 °C, 2013 |
Max 1hr Hum Rise |
8% |
15:43 |
8% |
20%, 2020 |
3%, 2022 |
Max 10m Temp Fall |
0.8 °C |
15:15 |
0.6 °C |
1.2 °C, 2020 |
0.2 °C, 2012 |
Max 1hr Temp Fall |
1.8 °C |
02:56 |
1.5 °C |
2.5 °C, 2020 |
0.4 °C, 2018 |
Max 1hr Hum Fall |
19% |
14:43 |
12% |
19%, 2016 |
3%, 2013 |
Max 10m Wind Speed |
7.5 mph |
00:10 |
9.4 mph |
17.3 mph, 2018 |
5.0 mph, 2021 |
Minimum Feels-like |
-0.7 °C |
07:05 |
-0.4 °C |
5.3 °C, 2019 |
-10.6 °C, 2018 |
Maximum Feels-like |
5.0 °C |
00:00 |
9.7 °C |
14.6 °C, 2019 |
-3.4 °C, 2018 |
Mean Feels-like |
1.3 °C |
|
4.0 °C |
10.4 °C, 2019 |
-7.8 °C, 2018 |
Air-frost Hrs |
0 hrs |
|
0 hrs |
24 hrs, 2018 |
0 hrs, 2009 |
Measure | Value (anomaly) |
Month cumul. | Record High | Record Low |
Temperature Range |
4.4 °C (-1.8) |
6.3 °C (+0.1) |
10.8 °C (+4.6), 2009 |
1.5 °C (-4.7), 2022 |
Humidity Range |
27% |
28% |
48%, 2015 |
10%, 2022 |
Pressure Range |
10 hPa |
16 hPa |
19 hPa, 2014 |
3 hPa, 2021 |
Measure | Value [% of max] |
Month cumul. | Record High | Record Low |
Sun Hours |
2 [20%] | 2.2 hrs (33%) [11%] |
10 [101%], 2010 |
0 [0%], 2018 |
Wet Hours |
3 [Mean rain rate: 0.6 mm/h] | 7 hrs (205%) [15%] |
9, 2022 |
, 2009 |
Cloud Cover |
Partly Cloudy with periods of Mostly Cloudy |
Events |
None |
Comments |
Showers |
Extra Comments |
|
Issues |
TODO: wind and harpenden down |
Observer Absent? |
Yes - observations may be unreliable |
Pond Temperature (Heath) |
0.0 °C |