Daily Report for 21st August 2019

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 10.8 °C (-2.3) 06:43 14.2 °C (+0.8) 19.0 °C (+5.9), 2010 7.7 °C (-5.4), 2014
Maximum Temperature 22.4 °C (+0.2) 13:37 22.4 °C (-0.0) 26.0 °C (+3.8), 2018 18.4 °C (-3.8), 2014
Mean Temperature 17.2 °C (-1.0) 18.2 °C (+0.4) 21.7 °C, 2018 13.5 °C, 2014
Minimum Humidity 50% 13:39 54% 79%, 2017 34%, 2013
Maximum Humidity 88% 07:02 90% 91%, 2010 83%, 2020
Mean Humidity 68% 74% 85%, 2010 57%, 2013
Minimum Pressure 1026 hPa 17:44 1010 hPa 1026 hPa, 2019 1000 hPa, 2020
Maximum Pressure 1029 hPa 08:59 1016 hPa 1029 hPa, 2019 1010 hPa, 2020
Mean Pressure 1027 hPa 1013 hPa 1027 hPa, 2019 1004 hPa, 2020
Mean Wind Speed 4.3 mph (+0.3) 5.6 mph (+1.6) 12.4 mph, 2020 0.8 mph, 2021
Maximum Wind Speed 11.9 mph 12:05 14.3 mph 28.6 mph, 2020 5.6 mph, 2021
Maximum Gust 19.6 mph 12:21 23.4 mph 43.8 mph, 2020 9.1 mph, 2021
Mean Wind Direction SW
Rainfall 0.0 mm 36.6 mm (108%) 4.3 mm, 2017
Maximum Hourly Rain n/a 1.3, 2017
Maximum 10-min Rain n/a 0.3, 2009
Maximum Rain Rate n/a 3, 2017
Minimum Dew Point 8.6 °C 04:28 11.2 °C 16.8 °C, 2010 4.2 °C, 2014
Maximum Dew Point 13.0 °C 10:18 15.4 °C 18.3 °C, 2010 9.1 °C, 2014
Mean Dew Point 11.0 °C 13.2 °C 17.6 °C, 2010 6.3 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 10.8 °C 06:41 14.4 °C 19.0 °C, 2010 7.7 °C, 2014
Day Maximum (09-21) 22.4 °C 13:37 22.4 °C 26.0 °C, 2018 18.4 °C, 2014
Max 10m Temp Rise 0.8 °C 07:22 0.7 °C 1.1 °C, 2009 0.2 °C, 2017
Max 1hr Temp Rise 3.5 °C 08:04 2.3 °C 3.8 °C, 2009 0.8 °C, 2017
Max 1hr Hum Rise 7% 19:42 12% 18%, 2016 3%, 2017
Max 10m Temp Fall 0.4 °C 18:49 0.7 °C 1.2 °C, 2009 0.1 °C, 2017
Max 1hr Temp Fall 1.7 °C 19:31 2.0 °C 2.7 °C, 2009 0.4 °C, 2017
Max 1hr Hum Fall 10% 08:09 12% 23%, 2009 2%, 2017
Max 10m Wind Speed 8.7 mph 13:41 10.7 mph 19.2 mph, 2020 3.7 mph, 2021
Minimum Feels-like 11.5 °C 06:32 16.5 °C 24.3 °C, 2010 6.0 °C, 2014
Maximum Feels-like 24.8 °C 16:14 25.6 °C 31.2 °C, 2018 18.4 °C, 2014
Mean Feels-like 19.0 °C 21.2 °C 26.5 °C, 2018 13.6 °C, 2014
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 11.6 °C (+2.5) 8.2 °C (-0.8) 14.1 °C (+5.0), 2013 3.1 °C (-6.0), 2010
Humidity Range 38% 36% 50%, 2013 7%, 2017
Pressure Range 3 hPa 6 hPa 12 hPa, 2016 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 8 [61%]106 hrs (82%) [37%] 11 [85%], 2013 0 [0%], 2017
Wet Hours 034 hrs (132%) [6.7%] 7, 2017 0, 2010
Cloud Cover am: Hazy
pm: Mostly Sunny
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 18.0 °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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Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

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Wind rose