Daily Report for 22nd January 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 1.3 °C (-1.0) 08:26 1.5 °C (-1.0) 7.6 °C (+5.3), 2018 -4.8 °C (-7.1), 2013
Maximum Temperature 6.6 °C (-0.4) 15:19 6.3 °C (-0.8) 11.6 °C (+4.6), 2012 2.5 °C (-4.5), 2013
Mean Temperature 3.8 °C (-0.7) 3.9 °C (-0.9) 8.8 °C, 2018 -0.5 °C, 2017
Minimum Humidity 69% 14:41 82% 90%, 2020 47%, 2012
Maximum Humidity 92% 09:16 94% 98%, 2010 79%, 2012
Mean Humidity 85% 90% 97%, 2010 63%, 2012
Minimum Pressure 988 hPa 00:00 1011 hPa 1037 hPa, 2020 983 hPa, 2009
Maximum Pressure 995 hPa 23:55 1019 hPa 1040 hPa, 2020 995 hPa, 2021
Mean Pressure 993 hPa 1015 hPa 1038 hPa, 2020 991 hPa, 2009
Mean Wind Speed 3.1 mph (-2.1) 4.8 mph (-0.5) 7.1 mph, 2012 0.3 mph, 2017
Maximum Wind Speed 10.7 mph 19:39 12.6 mph 19.0 mph, 2012 5.2 mph, 2017
Maximum Gust 18.2 mph 19:39 20.1 mph 24.6 mph, 2012 7.3 mph, 2017
Mean Wind Direction W
Rainfall 0.0 mm 48.5 mm (124%) 9.0 mm, 2010
Maximum Hourly Rain n/a 4.3, 2014
Maximum 10-min Rain n/a 0.9, 2014
Maximum Rain Rate n/a 13, 2019
Minimum Dew Point -0.1 °C 06:13 0.0 °C 4.1 °C, 2014 -7.6 °C, 2017
Maximum Dew Point 3.3 °C 20:03 4.5 °C 9.2 °C, 2018 0.4 °C, 2015
Mean Dew Point 1.6 °C 2.4 °C 6.4 °C, 2010 -4.4 °C, 2017
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 1.3 °C 08:23 2.2 °C 7.7 °C, 2018 -4.8 °C, 2013
Day Maximum (09-21) 6.6 °C 14:57 6.0 °C 11.6 °C, 2012 2.5 °C, 2013
Max 10m Temp Rise 0.4 °C 11:00 0.3 °C 0.5 °C, 2012 0.1 °C, 2010
Max 1hr Temp Rise 1.7 °C 11:55 1.0 °C 1.7 °C, 2017 0.6 °C, 2010
Max 1hr Hum Rise 6% 17:02 4% 12%, 2019 2%, 2020
Max 10m Temp Fall 0.4 °C 17:36 0.4 °C 0.8 °C, 2019 0.1 °C, 2010
Max 1hr Temp Fall 1.4 °C 17:40 1.2 °C 2.2 °C, 2017 0.2 °C, 2010
Max 1hr Hum Fall 9% 13:50 5% 12%, 2012 0%, 2010
Max 10m Wind Speed 8.5 mph 19:45 9.9 mph 12.5 mph, 2012 4.5 mph, 2017
Minimum Feels-like -2.8 °C 09:17 -2.9 °C 4.6 °C, 2018 -8.8 °C, 2013
Maximum Feels-like 6.3 °C 16:20 5.9 °C 11.6 °C, 2012 1.1 °C, 2013
Mean Feels-like 1.9 °C 1.8 °C 7.1 °C, 2018 -2.6 °C, 2013
Air-frost Hrs 0 hrs 2 hrs 16 hrs, 2017 0 hrs, 2010
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.3 °C (+0.6) 4.8 °C (+0.2) 8.6 °C (+3.9), 2017 2.5 °C (-2.2), 2018
Humidity Range 23% 11% 35%, 2009 5%, 2020
Pressure Range 7 hPa 8 hPa 16 hPa, 2009 2 hPa, 2017
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 6 [78%]31 hrs (74%) [19%] 7 [91%], 2017 0 [0%], 2010
Wet Hours 054 hrs (113%) [10%] 12, 2010 , 2009
Cloud Cover am: Sunny
pm: Sunny transitioned to Partly Cloudy
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