Daily Report for 9th February 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature -1.7 °C (-4.0) 00:55 2.1 °C (-0.2) 8.7 °C (+6.4), 2020 -1.7 °C (-4.0), 2021
Maximum Temperature -0.2 °C (-7.4) 15:16 6.1 °C (-1.1) 12.4 °C (+5.2), 2020 -0.2 °C (-7.4), 2021
Mean Temperature -0.9 °C (-5.7) 4.4 °C (-0.7) 10.3 °C, 2020 -0.9 °C, 2021
Minimum Humidity 80% 19:05 81% 95%, 2009 52%, 2014
Maximum Humidity 90% 12:16 94% 98%, 2009 76%, 2014
Mean Humidity 85% 88% 96%, 2009 64%, 2014
Minimum Pressure 1007 hPa 00:02 1002 hPa 1037 hPa, 2012 978 hPa, 2014
Maximum Pressure 1010 hPa 23:50 1007 hPa 1041 hPa, 2012 990 hPa, 2014
Mean Pressure 1008 hPa 1004 hPa 1039 hPa, 2012 984 hPa, 2014
Mean Wind Speed 5.2 mph (+0.1) 5.1 mph (-0.0) 16.4 mph, 2020 1.5 mph, 2012
Maximum Wind Speed 12.3 mph 12:14 13.6 mph 34.0 mph, 2020 7.8 mph, 2012
Maximum Gust 21.7 mph 22:34 21.2 mph 57.6 mph, 2020 10.0 mph, 2012
Mean Wind Direction ENE
Rainfall / Snow-melt approx. 1.0 mm 30.8 mm (234%) 20.0 mm, 2009
Maximum Hourly Rain n/a 5, 2020
Maximum 10-min Rain n/a 4, 2020
Maximum Rain Rate n/a 66, 2020
Minimum Dew Point -3.7 °C 04:34 0.4 °C 4.7 °C, 2020 -4.5 °C, 2012
Maximum Dew Point -2.0 °C 12:16 4.3 °C 10.8 °C, 2020 -2.0 °C, 2021
Mean Dew Point -3.1 °C 2.7 °C 7.7 °C, 2020 -3.2 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) -1.7 °C 02:07 2.9 °C 7.8 °C, 2020 -1.7 °C, 2021
Day Maximum (09-21) -0.2 °C 15:16 5.8 °C 12.4 °C, 2020 -0.2 °C, 2021
Max 10m Temp Rise 0.2 °C 10:14 0.3 °C 0.5 °C, 2011 0.1 °C, 2017
Max 1hr Temp Rise 0.6 °C 10:14 1.1 °C 2.0 °C, 2011 0.2 °C, 2017
Max 1hr Hum Rise 6% 21:35 5% 11%, 2016 1%, 2009
Max 10m Temp Fall 0.2 °C 15:29 0.3 °C 1.6 °C, 2020 0.1 °C, 2017
Max 1hr Temp Fall 0.5 °C 21:43 0.9 °C 2.2 °C, 2015 0.4 °C, 2017
Max 1hr Hum Fall 5% 14:45 6% 13%, 2016 1%, 2009
Max 10m Wind Speed 9.4 mph 12:16 10.6 mph 24.0 mph, 2020 5.7 mph, 2012
Minimum Feels-like -8.0 °C 22:34 -2.8 °C 3.3 °C, 2011 -8.0 °C, 2021
Maximum Feels-like -0.4 °C 20:25 5.7 °C 14.1 °C, 2020 -0.4 °C, 2021
Mean Feels-like -5.3 °C 1.9 °C 9.1 °C, 2020 -5.3 °C, 2021
Air-frost Hrs 24 hrs 6 hrs 24 hrs, 2021 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 1.5 °C (-3.4) 4.1 °C (-0.8) 6.8 °C (+1.9), 2015 0.9 °C (-4.0), 2017
Humidity Range 10% 13% 30%, 2018 3%, 2009
Pressure Range 2 hPa 6 hPa 25 hPa, 2020 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]1.5 hrs (7%) [2%] 5 [58%], 2015 0 [0%], 2009
Wet Hours 3
[Mean rain rate: 0.3 mm/h]
38 hrs (227%) [18%] 8, 2018 , 2009
Cloud Cover Overcast with periods of Mostly Cloudy
Events Snowfall: ~1 cm
Lying Snow (at 09z): ~2 cm
Air Frost
Comments Light sn flurries
Extra Comments new snow did not settle
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

daycamsumFull resolution individual images at up-to 5 minute intervals

Wind rose