Daily Report for 17th June 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.0 °C (+1.8) 05:49 11.1 °C (+0.3) 16.0 °C (+4.8), 2017 8.3 °C (-2.9), 2010
Maximum Temperature 22.4 °C (+1.9) 12:06 19.9 °C (+0.2) 30.1 °C (+9.6), 2017 14.8 °C (-5.7), 2011
Mean Temperature 17.8 °C (+1.8) 15.6 °C (+0.2) 23.9 °C, 2017 12.5 °C, 2011
Minimum Humidity 58% 12:08 53% 72%, 2011 35%, 2010
Maximum Humidity 91% 07:02 89% 95%, 2011 77%, 2015
Mean Humidity 74% 71% 86%, 2011 59%, 2017
Minimum Pressure 1013 hPa 18:20 1010 hPa 1026 hPa, 2014 995 hPa, 2011
Maximum Pressure 1014 hPa 01:06 1015 hPa 1028 hPa, 2014 1011 hPa, 2011
Mean Pressure 1014 hPa 1013 hPa 1027 hPa, 2014 1003 hPa, 2011
Mean Wind Speed 1.3 mph (-3.1) 4.0 mph (-0.4) 7.1 mph, 2015 1.3 mph, 2020
Maximum Wind Speed 9.1 mph 19:51 12.3 mph 17.0 mph, 2019 8.8 mph, 2017
Maximum Gust 12.7 mph 12:45 19.6 mph 26.6 mph, 2015 11.5 mph, 2017
Mean Wind Direction SE
Rainfall 2.1 mm 14.3 mm (56%) 7.6 mm, 2011
Maximum Hourly Rain 1.4 mm 23:54 5.5 mm, 2016
Maximum 10-min Rain 0.5 mm 23:32 3.1 mm, 2016
Maximum Rain Rate 18 mm/h 23:54 54 mm/h, 2016
Minimum Dew Point 10.9 °C 04:39 8.0 °C 12.4 °C, 2017 3.8 °C, 2014
Maximum Dew Point 15.2 °C 15:00 12.3 °C 16.6 °C, 2017 9.6 °C, 2014
Mean Dew Point 13.1 °C 10.1 °C 15.0 °C, 2017 8.0 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.0 °C 05:49 11.3 °C 16.0 °C, 2017 8.3 °C, 2010
Day Maximum (09-21) 22.4 °C 12:06 19.9 °C 30.1 °C, 2017 14.8 °C, 2011
Max 10m Temp Rise 0.6 °C 07:10 0.6 °C 0.8 °C, 2012 0.3 °C, 2011
Max 1hr Temp Rise 2.7 °C 07:54 2.2 °C 2.8 °C, 2019 1.2 °C, 2011
Max 1hr Hum Rise 12% 14:02 11% 17%, 2014 7%, 2011
Max 10m Temp Fall 0.6 °C 13:31 0.8 °C 0.8 °C, 2016 0.3 °C, 2013
Max 1hr Temp Fall 2.3 °C 13:47 2.0 °C 2.4 °C, 2017 1.1 °C, 2013
Max 1hr Hum Fall 13% 08:02 12% 13%, 2018 7%, 2009
Max 10m Wind Speed 5.5 mph 13:04 9.0 mph 12.4 mph, 2015 5.5 mph, 2020
Minimum Feels-like 14.7 °C 05:33 11.4 °C 18.5 °C, 2017 6.9 °C, 2010
Maximum Feels-like 25.8 °C 12:00 21.7 °C 35.0 °C, 2017 16.2 °C, 2011
Mean Feels-like 20.7 °C 17.0 °C 27.8 °C, 2017 13.8 °C, 2011
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 9.4 °C (+0.1) 8.7 °C (-0.2) 15.0 °C (+5.7), 2010 4.9 °C (-4.4), 2011
Humidity Range 33% 36% 50%, 2010 23%, 2011
Pressure Range 2 hPa 5 hPa 16 hPa, 2011 2 hPa, 2020
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.5 [3%]88 hrs (87%) [34%] 13 [86%], 2010 0.3 [2%], 2011
Wet Hours 2
[Mean rain rate: 1.1 mm/h]		15 hrs (70%) [3.6%] 7, 2011 0, 2010
Cloud Cover Overcast
Events Thunder
Comments Showers, late rn - maybe thunder
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 5.0 °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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