Daily Report for 12th April 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 0.7 °C (-4.1) 05:01 2.8 °C (-1.9) 11.1 °C (+6.3), 2020 0.7 °C (-4.1), 2021
Maximum Temperature 9.7 °C (-2.6) 16:25 10.3 °C (-1.7) 24.9 °C (+12.6), 2020 9.7 °C (-2.6), 2021
Mean Temperature 4.5 °C (-3.3) 6.3 °C (-1.8) 17.2 °C, 2020 4.5 °C, 2021
Minimum Humidity 38% 16:29 49% 92%, 2009 32%, 2020
Maximum Humidity 87% 00:01 84% 97%, 2009 75%, 2015
Mean Humidity 67% 68% 95%, 2009 54%, 2015
Minimum Pressure 1027 hPa 00:02 1020 hPa 1027 hPa, 2021 993 hPa, 2013
Maximum Pressure 1033 hPa 23:55 1027 hPa 1033 hPa, 2021 1005 hPa, 2012
Mean Pressure 1030 hPa 1024 hPa 1030 hPa, 2021 997 hPa, 2013
Mean Wind Speed 1.3 mph (-3.6) 5.0 mph (+0.1) 7.8 mph, 2015 1.3 mph, 2021
Maximum Wind Speed 7.9 mph 14:08 13.6 mph 20.6 mph, 2015 7.9 mph, 2021
Maximum Gust 13.7 mph 14:13 20.7 mph 29.9 mph, 2015 13.7 mph, 2021
Mean Wind Direction N
Rainfall 0.0 mm 0.1 mm (1%) 10.2 mm, 2013
Maximum Hourly Rain n/a 3.8, 2012
Maximum 10-min Rain n/a 2.3, 2012
Maximum Rain Rate n/a 20, 2012
Minimum Dew Point -4.8 °C 19:21 -2.4 °C 8.2 °C, 2009 -4.8 °C, 2021
Maximum Dew Point 1.5 °C 11:14 3.5 °C 10.8 °C, 2009 1.5 °C, 2021
Mean Dew Point -1.6 °C 0.6 °C 9.2 °C, 2009 -1.6 °C, 2021
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 0.7 °C 05:04 3.3 °C 11.1 °C, 2020 0.7 °C, 2021
Day Maximum (09-21) 9.7 °C 16:26 10.0 °C 24.9 °C, 2020 9.7 °C, 2021
Max 10m Temp Rise 0.6 °C 11:01 0.6 °C 1.0 °C, 2009 0.4 °C, 2010
Max 1hr Temp Rise 2.0 °C 11:11 1.7 °C 3.4 °C, 2012 1.2 °C, 2009
Max 1hr Hum Rise 12% 20:21 12% 20%, 2012 2%, 2009
Max 10m Temp Fall 0.6 °C 20:16 0.7 °C 2.0 °C, 2015 0.3 °C, 2010
Max 1hr Temp Fall 2.8 °C 20:47 1.9 °C 5.1 °C, 2015 0.5 °C, 2009
Max 1hr Hum Fall 12% 11:50 11% 19%, 2016 2%, 2009
Max 10m Wind Speed 6.1 mph 13:28 10.2 mph 16.2 mph, 2015 6.1 mph, 2021
Minimum Feels-like -1.6 °C 04:57 -1.1 °C 11.3 °C, 2020 -2.5 °C, 2019
Maximum Feels-like 9.5 °C 16:50 9.5 °C 25.3 °C, 2020 9.3 °C, 2019
Mean Feels-like 3.7 °C 4.3 °C 17.8 °C, 2020 3.7 °C, 2021
Air-frost Hrs 0 hrs 0.7 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 9.0 °C (+1.5) 7.5 °C (+0.2) 14.4 °C (+6.9), 2015 3.2 °C (-4.3), 2009
Humidity Range 49% 34% 49%, 2020 5%, 2009
Pressure Range 7 hPa 7 hPa 14 hPa, 2013 2 hPa, 2016
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 4 [33%]52 hrs (91%) [36%] 11 [90%], 2011 0 [0%], 2009
Wet Hours 00.4 hrs (2%) [0.1%] 6, 2013 0, 2010
Cloud Cover unknown
Events None
Comments blr
Extra Comments
Issues None known
Observer Absent? No
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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