Daily Report for 19th March 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 3.9 °C (+0.0) 23:59 3.7 °C (+0.5) 11.9 °C (+8.0), 2017 -1.6 °C (-5.5), 2011
Maximum Temperature 10.3 °C (-0.3) 13:42 9.1 °C (-0.7) 15.9 °C (+5.3), 2014 3.2 °C (-7.4), 2018
Mean Temperature 7.5 °C (-0.1) 6.4 °C (-0.1) 13.0 °C, 2017 0.8 °C, 2018
Minimum Humidity 57% 13:42 67% 84%, 2020 38%, 2012
Maximum Humidity 93% 01:39 90% 97%, 2010 80%, 2014
Mean Humidity 78% 80% 92%, 2020 64%, 2012
Minimum Pressure 1025 hPa 00:05 1018 hPa 1030 hPa, 2011 994 hPa, 2013
Maximum Pressure 1034 hPa 23:20 1026 hPa 1035 hPa, 2011 999 hPa, 2013
Mean Pressure 1029 hPa 1022 hPa 1032 hPa, 2011 997 hPa, 2013
Mean Wind Speed 5.6 mph (+0.4) 5.5 mph (+0.3) 9.6 mph, 2018 1.6 mph, 2011
Maximum Wind Speed 14.5 mph 03:48 14.1 mph 21.7 mph, 2018 6.2 mph, 2011
Maximum Gust 22.8 mph 03:48 21.3 mph 31.4 mph, 2017 8.5 mph, 2011
Mean Wind Direction NE
Rainfall 0.0 mm 17.7 mm (69%) 4.9 mm, 2010
Maximum Hourly Rain n/a 1.9, 2010
Maximum 10-min Rain n/a 1.1, 2010
Maximum Rain Rate n/a 16, 2010
Minimum Dew Point 1.6 °C 23:59 1.0 °C 6.9 °C, 2017 -6.3 °C, 2018
Maximum Dew Point 6.0 °C 00:00 5.3 °C 10.9 °C, 2010 -2.4 °C, 2018
Mean Dew Point 3.7 °C 3.0 °C 9.1 °C, 2010 -4.6 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 5.4 °C * 08:03 4.0 °C 12.0 °C, 2017 -1.6 °C, 2011
Day Maximum (09-21) 10.3 °C 13:51 9.1 °C 15.9 °C, 2014 3.2 °C, 2018
Max 10m Temp Rise 0.5 °C 09:10 0.5 °C 1.8 °C, 2009 0.2 °C, 2015
Max 1hr Temp Rise 1.7 °C 09:46 1.4 °C 4.9 °C, 2011 0.5 °C, 2020
Max 1hr Hum Rise 13% 18:17 8% 13%, 2021 2%, 2015
Max 10m Temp Fall 0.4 °C 18:08 0.5 °C 1.3 °C, 2009 0.2 °C, 2010
Max 1hr Temp Fall 1.3 °C 21:44 1.4 °C 3.2 °C, 2009 0.5 °C, 2015
Max 1hr Hum Fall 8% 09:19 8% 14%, 2012 4%, 2020
Max 10m Wind Speed 10.2 mph 03:52 10.6 mph 16.1 mph, 2018 4.5 mph, 2011
Minimum Feels-like 1.3 °C 08:07 0.2 °C 12.3 °C, 2017 -8.0 °C, 2018
Maximum Feels-like 10.3 °C 13:41 9.1 °C 15.9 °C, 2014 -0.9 °C, 2018
Mean Feels-like 5.2 °C 4.5 °C 13.5 °C, 2017 -4.6 °C, 2018
Air-frost Hrs 0 hrs 0.2 hrs 6 hrs, 2018 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 6.4 °C (-0.3) 5.4 °C (-1.2) 12.7 °C (+6.0), 2011 2.2 °C (-4.5), 2015
Humidity Range 36% 23% 55%, 2011 10%, 2020
Pressure Range 9 hPa 9 hPa 12 hPa, 2018 2 hPa, 2016
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 9 [83%]48 hrs (77%) [25%] 10.9 [101%], 2011 0 [0%], 2015
Wet Hours 023 hrs (71%) [5%] 5, 2010 , 2009
Cloud Cover Mostly Sunny with periods of Sunny
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 4.5 °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