Daily Report for 24th November 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 9.1 °C (+5.2) 23:28 7.0 °C (+1.7) 9.1 °C (+5.2), 2020 -0.3 °C (-4.2), 2017
Maximum Temperature 11.8 °C (+2.3) 13:45 12.8 °C (+2.5) 14.0 °C (+4.5), 2009 4.3 °C (-5.2), 2010
Mean Temperature 10.5 °C (+3.8) 10.1 °C (+2.1) 11.9 °C, 2009 2.5 °C, 2010
Minimum Humidity 74% 13:29 76% 93%, 2012 67%, 2017
Maximum Humidity 90% 23:36 94% 98%, 2011 78%, 2016
Mean Humidity 85% 86% 98%, 2012 76%, 2016
Minimum Pressure 1012 hPa 23:47 1015 hPa 1027 hPa, 2013 993 hPa, 2012
Maximum Pressure 1024 hPa 00:02 1025 hPa 1034 hPa, 2013 1006 hPa, 2019
Mean Pressure 1018 hPa 1020 hPa 1030 hPa, 2013 1003 hPa, 2009
Mean Wind Speed 6.7 mph (+2.1) 5.0 mph (+0.4) 9.9 mph, 2009 1.0 mph, 2014
Maximum Wind Speed 14.4 mph 12:14 12.8 mph 19.6 mph, 2009 4.7 mph, 2014
Maximum Gust 22.8 mph 12:14 20.9 mph 29.9 mph, 2009 7.1 mph, 2014
Mean Wind Direction SSW
Rainfall 0.0 mm 32.2 mm (67%) 10.0 mm, 2012
Maximum Hourly Rain n/a 3.1, 2015
Maximum 10-min Rain n/a 1.1, 2015
Maximum Rain Rate n/a 36, 2015
Minimum Dew Point 7.3 °C 14:58 5.1 °C 7.3 °C, 2020 -1.3 °C, 2010
Maximum Dew Point 9.2 °C 04:40 10.5 °C 11.4 °C, 2009 1.2 °C, 2010
Mean Dew Point 8.1 °C 7.9 °C 9.1 °C, 2009 -0.1 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 8.6 °C * 22:32 8.1 °C 9.2 °C, 2016 0.6 °C, 2010
Day Maximum (09-21) 11.8 °C 13:45 12.6 °C 14.0 °C, 2009 4.3 °C, 2010
Max 10m Temp Rise 0.2 °C 12:04 0.4 °C 1.4 °C, 2009 0.1 °C, 2016
Max 1hr Temp Rise 0.6 °C 12:11 1.4 °C 2.7 °C, 2009 0.4 °C, 2016
Max 1hr Hum Rise 4% 16:52 6% 10%, 2009 1%, 2016
Max 10m Temp Fall 0.2 °C 14:54 0.5 °C 0.5 °C, 2009 0.2 °C, 2015
Max 1hr Temp Fall 0.6 °C 14:54 1.3 °C 2.5 °C, 2017 0.4 °C, 2016
Max 1hr Hum Fall 4% 10:41 7% 12%, 2009 1%, 2012
Max 10m Wind Speed 13.8 mph 11:09 8.5 mph 13.8 mph, 2020 3.9 mph, 2014
Minimum Feels-like 6.4 °C 23:42 5.8 °C 6.4 °C, 2011 -2.5 °C, 2010
Maximum Feels-like 12.1 °C 12:35 14.3 °C 15.3 °C, 2009 4.3 °C, 2010
Mean Feels-like 10.4 °C 10.6 °C 12.6 °C, 2009 1.2 °C, 2010
Air-frost Hrs 0 hrs 0 hrs 0.9 hrs, 2017 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 2.7 °C (-2.9) 5.8 °C (+0.8) 8.7 °C (+3.1), 2017 2.4 °C (-3.2), 2018
Humidity Range 16% 18% 28%, 2017 5%, 2012
Pressure Range 12 hPa 10 hPa 23 hPa, 2012 2 hPa, 2016
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [27%]61 hrs (103%) [32%] 5.5 [73%], 2010 0 [0%], 2009
Wet Hours 044 hrs (86%) [7.6%] 13, 2012 0, 2010
Cloud Cover am: Mostly Cloudy
pm: Hazy
Events None
Comments -
Extra Comments
Issues wind from harpenden
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 10.5 °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