Daily Report for 20th May 2022

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 12.4 °C (+2.9) 12:15 10.6 °C (+2.2) 14.1 °C (+4.6), 2014 5.1 °C (-4.4), 2015
Maximum Temperature 17.8 °C (-0.4) 16:50 19.6 °C (+2.3) 27.4 °C (+9.2), 2020 11.7 °C (-6.5), 2012
Mean Temperature 14.6 °C (+1.3) 15.0 °C (+2.3) 21.1 °C, 2020 10.1 °C, 2012
Minimum Humidity 59% 00:00 55% 80%, 2012 36%, 2020
Maximum Humidity 88% 11:46 90% 93%, 2013 67%, 2011
Mean Humidity 75% 74% 85%, 2013 53%, 2011
Minimum Pressure 1018 hPa 17:15 1019 hPa 1030 hPa, 2010 1002 hPa, 2021
Maximum Pressure 1022 hPa 00:23 1024 hPa 1033 hPa, 2010 1010 hPa, 2014
Mean Pressure 1020 hPa 1021 hPa 1032 hPa, 2010 1006 hPa, 2014
Mean Wind Speed 4.8 mph (+0.1) 3.6 mph (-1.1) 8.1 mph, 2021 1.5 mph, 2019
Maximum Wind Speed 13.9 mph 15:57 12.0 mph 22.2 mph, 2021 7.1 mph, 2010
Maximum Gust 20.5 mph 23:27 18.5 mph 35.4 mph, 2021 10.0 mph, 2010
Mean Wind Direction W
Rainfall 4.1 mm 18.8 mm (63%) 4.1 mm, 2022
Maximum Hourly Rain 1.9 mm 12:09 1.9 mm, 2022
Maximum 10-min Rain 0.8 mm 11:48 0.8 mm, 2017
Maximum Rain Rate 4.8 mm/h 11:39 18 mm/h, 2017
Minimum Dew Point 7.8 °C 00:00 7.6 °C 8.3 °C, 2010 1.1 °C, 2015
Maximum Dew Point 11.9 °C 19:33 12.5 °C 14.9 °C, 2010 5.7 °C, 2015
Mean Dew Point 10.1 °C 10.1 °C 11.6 °C, 2010 3.2 °C, 2015
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 13.1 °C * 05:31 10.7 °C 15.3 °C, 2014 5.1 °C, 2015
Day Maximum (09-21) 17.8 °C 16:50 19.6 °C 27.4 °C, 2020 11.7 °C, 2012
Max 10m Temp Rise 0.5 °C 13:47 0.6 °C 0.9 °C, 2009 0.4 °C, 2012
Max 1hr Temp Rise 2.0 °C 15:27 2.3 °C 3.5 °C, 2020 1.1 °C, 2012
Max 1hr Hum Rise 12% 10:31 11% 16%, 2021 2%, 2012
Max 10m Temp Fall 0.5 °C 12:02 0.5 °C 0.9 °C, 2017 0.2 °C, 2012
Max 1hr Temp Fall 1.1 °C 20:25 1.8 °C 2.8 °C, 2019 0.5 °C, 2012
Max 1hr Hum Fall 13% 15:21 11% 15%, 2018 5%, 2012
Max 10m Wind Speed 10.4 mph 16:06 9.0 mph 19.0 mph, 2021 4.9 mph, 2019
Minimum Feels-like 13.5 °C 23:59 10.9 °C 14.9 °C, 2016 2.0 °C, 2015
Maximum Feels-like 19.9 °C 16:42 21.6 °C 30.5 °C, 2020 12.4 °C, 2012
Mean Feels-like 15.9 °C 16.4 °C 23.1 °C, 2020 9.5 °C, 2015
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.4 °C (-3.3) 9.0 °C (+0.2) 15.1 °C (+6.4), 2020 3.1 °C (-5.6), 2012
Humidity Range 29% 35% 50%, 2020 7%, 2012
Pressure Range 4 hPa 5 hPa 20 hPa, 2021 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [14%]105 hrs (87%) [38%] 14.4 [100%], 2018 0 [0%], 2012
Wet Hours 4
[Mean rain rate: 1.0 mm/h]
25 hrs (96%) [5.2%] 4, 2022 0, 2009
Cloud Cover unknown
Events None
Comments blr
Extra Comments
Issues None known
Observer Absent? No
Pond Temperature (Heath) 17.0 °C
Notes
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 initially pulled from the official weather station at Heathrow, and later adjusted by hand to reflect local conditions based on webcam observations. Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually. Cloud cover and Events are manually reported, often with multi-week delays.
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Webcam Summary of Cloud Conditions

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