Daily Report for 27th January 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 6.4 °C (+4.1) 00:05 1.3 °C (-1.1) 7.6 °C (+5.3), 2016 -2.7 °C (-5.0), 2010
Maximum Temperature 9.5 °C (+2.5) 14:50 6.0 °C (-1.0) 13.3 °C (+6.3), 2016 2.6 °C (-4.4), 2011
Mean Temperature 8.3 °C (+3.3) 3.7 °C (-1.1) 11.8 °C, 2016 1.5 °C, 2010
Minimum Humidity 92% 16:31 83% 92%, 2021 49%, 2013
Maximum Humidity 96% 05:37 94% 98%, 2010 78%, 2011
Mean Humidity 95% 90% 95%, 2021 68%, 2011
Minimum Pressure 1008 hPa 23:59 1009 hPa 1023 hPa, 2018 984 hPa, 2019
Maximum Pressure 1014 hPa 10:24 1018 hPa 1040 hPa, 2010 992 hPa, 2014
Mean Pressure 1012 hPa 1014 hPa 1028 hPa, 2010 989 hPa, 2014
Mean Wind Speed 1.4 mph (-3.8) 4.4 mph (-0.8) 10.7 mph, 2016 1.4 mph, 2021
Maximum Wind Speed 8.2 mph 01:36 12.2 mph 21.9 mph, 2016 8.2 mph, 2021
Maximum Gust 14.8 mph 01:39 19.5 mph 33.4 mph, 2016 13.5 mph, 2012
Mean Wind Direction NW
Rainfall 4.8 mm 60.7 mm (127%) 8.4 mm, 2020
Maximum Hourly Rain 1.5 mm 20:26 4.4 mm, 2020
Maximum 10-min Rain 0.5 mm 19:48 1.5 mm, 2020
Maximum Rain Rate 2.9 mm/h 19:48 30 mm/h, 2020
Minimum Dew Point 5.7 °C 00:05 -0.2 °C 5.7 °C, 2021 -6.0 °C, 2011
Maximum Dew Point 8.6 °C 21:21 4.4 °C 11.4 °C, 2016 -1.7 °C, 2011
Mean Dew Point 7.5 °C 2.2 °C 9.6 °C, 2016 -3.7 °C, 2011
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 5.7 °C * 21:09 1.9 °C 11.5 °C, 2016 -2.7 °C, 2010
Day Maximum (09-21) 9.5 °C 14:50 5.7 °C 13.3 °C, 2016 2.6 °C, 2011
Max 10m Temp Rise 0.2 °C 10:00 0.3 °C 0.5 °C, 2017 0.1 °C, 2011
Max 1hr Temp Rise 0.5 °C 10:44 1.1 °C 2.0 °C, 2017 0.5 °C, 2011
Max 1hr Hum Rise 2% 18:50 4% 13%, 2012 1%, 2016
Max 10m Temp Fall 0.2 °C 18:12 0.4 °C 1.2 °C, 2012 0.2 °C, 2010
Max 1hr Temp Fall 0.3 °C 18:12 1.1 °C 2.8 °C, 2012 0.3 °C, 2017
Max 1hr Hum Fall 2% 14:50 5% 18%, 2013 2%, 2021
Max 10m Wind Speed 6.3 mph 01:39 9.6 mph 17.3 mph, 2016 6.3 mph, 2021
Minimum Feels-like 2.9 °C 01:39 -2.9 °C 3.7 °C, 2016 -5.0 °C, 2011
Maximum Feels-like 10.1 °C 14:39 5.7 °C 15.3 °C, 2016 1.9 °C, 2011
Mean Feels-like 7.8 °C 1.6 °C 12.7 °C, 2016 -2.6 °C, 2011
Air-frost Hrs 0 hrs 3 hrs 8 hrs, 2010 0 hrs, 2011
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.1 °C (-1.6) 4.8 °C (+0.2) 8.7 °C (+4.0), 2017 1.5 °C (-3.2), 2011
Humidity Range 4% 11% 49%, 2013 4%, 2021
Pressure Range 6 hPa 8 hPa 23 hPa, 2010 5 hPa, 2014
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]39 hrs (75%) [19%] 7.5 [95%], 2012 0 [0%], 2010
Wet Hours 6
[Mean rain rate: 0.8 mm/h]
72 hrs (123%) [11%] 7, 2013 , 2009
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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Webcam Summary of Cloud Conditions

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