Daily Report for 24th May 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 7.4 °C (-2.6) 05:11 7.2 °C (-1.5) 14.4 °C (+4.4), 2010 5.4 °C (-4.6), 2013
Maximum Temperature 13.4 °C (-5.2) 09:53 14.7 °C (-2.8) 28.8 °C (+10.2), 2010 8.9 °C (-9.7), 2013
Mean Temperature 10.1 °C (-3.9) 10.8 °C (-2.1) 20.9 °C, 2010 6.8 °C, 2013
Minimum Humidity 66% 15:17 55% 73%, 2013 32%, 2010
Maximum Humidity 93% 06:22 90% 94%, 2018 69%, 2010
Mean Humidity 83% 76% 83%, 2021 51%, 2011
Minimum Pressure 1003 hPa 00:08 1004 hPa 1028 hPa, 2020 1002 hPa, 2022
Maximum Pressure 1010 hPa 23:58 1012 hPa 1034 hPa, 2020 1010 hPa, 2021
Mean Pressure 1004 hPa 1008 hPa 1031 hPa, 2020 1004 hPa, 2021
Mean Wind Speed 5.2 mph (+0.5) 5.3 mph (+0.6) 7.3 mph, 2025 1.2 mph, 2017
Maximum Wind Speed 18.0 mph 10:13 16.4 mph 18.9 mph, 2022 7.7 mph, 2017
Maximum Gust 26.2 mph 10:12 24.8 mph 26.6 mph, 2013 10.5 mph, 2017
Mean Wind Direction WSW
Rainfall 8.6 mm 71.6 mm (201%) 9.3 mm, 2013
Maximum Hourly Rain 2.9 mm 20:42 5.2 mm, 2025
Maximum 10-min Rain 0.8 mm 00:47 2.0 mm, 2019
Maximum Rain Rate 4.8 mm/h 00:44 26 mm/h, 2019
Minimum Dew Point 6.0 °C 04:57 4.0 °C 12.6 °C, 2012 0.7 °C, 2011
Maximum Dew Point 9.0 °C 10:04 8.8 °C 17.6 °C, 2012 5.1 °C, 2011
Mean Dew Point 7.3 °C 6.5 °C 15.5 °C, 2012 3.1 °C, 2011
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 7.4 °C 05:11 7.5 °C 15.2 °C, 2010 5.4 °C, 2013
Day Maximum (09-21) 13.4 °C 12:25 14.7 °C 28.8 °C, 2010 8.9 °C, 2013
Max 10m Temp Rise 0.9 °C 14:17 0.7 °C 0.9 °C, 2009 0.4 °C, 2010
Max 1hr Temp Rise 2.6 °C 14:52 2.1 °C 3.9 °C, 2009 1.5 °C, 2025
Max 1hr Hum Rise 17% 12:26 15% 20%, 2019 5%, 2009
Max 10m Temp Fall 1.4 °C 11:55 0.8 °C 2.3 °C, 2022 0.3 °C, 2025
Max 1hr Temp Fall 3.0 °C 15:57 2.1 °C 4.0 °C, 2010 1.2 °C, 2025
Max 1hr Hum Fall 16% 17:46 12% 22%, 2016 6%, 2024
Max 10m Wind Speed 13.5 mph 13:40 12.5 mph 13.5 mph, 2021 5.1 mph, 2017
Minimum Feels-like 4.1 °C 05:18 4.9 °C 16.9 °C, 2012 1.5 °C, 2013
Maximum Feels-like 14.1 °C 09:53 15.3 °C 31.4 °C, 2012 8.2 °C, 2013
Mean Feels-like 9.3 °C 10.6 °C 24.5 °C, 2012 4.4 °C, 2013
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 6.0 °C (-2.6) 7.5 °C (-1.3) 14.8 °C (+6.2), 2009 3.5 °C (-5.1), 2013
Humidity Range 27% 35% 43%, 2016 18%, 2013
Pressure Range 8 hPa 8 hPa 14 hPa, 2013 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 5 [34%]88 hrs (61%) [26%] 14.5 [100%], 2009 0.1 [1%], 2013
Wet Hours 6
[Mean rain rate: 1.4 mm/h]		66 hrs (213%) [11%] 8, 2013 0, 2009
Cloud Cover Partly Cloudy with periods of Mostly Cloudy
Events None
Comments ample shs
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 14.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 24th May 2021.
Times of extremes are computed using the midpoint of the longest continuous period at that extreme value.
Cumulative anomalies are reported according to the expected value for the month-to-date rather than month-end.
Sun hrs are derived based on analysis of webcam observations, but may use data from our closest site, Heathrow, when needed.
Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually.
Rainfall totals may be manually adjusted after the fact to correct delayed or erroneous data.
Cloud cover and Events are manually reported, often with multi-week delays.
Data is generally reliable and accurate but should always be viewed with some quantity of salt to hand.
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Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

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