Daily Report for 20th March 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 2.9 °C (-1.7) 01:47 3.7 °C (-0.4) 10.6 °C (+6.0), 2024 0.7 °C (-3.9), 2018
Maximum Temperature 10.4 °C (-0.9) 16:54 9.2 °C (-1.3) 16.7 °C (+5.4), 2024 5.8 °C (-5.5), 2013
Mean Temperature 7.3 °C (-1.3) 6.4 °C (-0.8) 13.1 °C, 2024 3.4 °C, 2013
Minimum Humidity 75% 16:52 67% 92%, 2010 44%, 2022
Maximum Humidity 90% 02:04 90% 98%, 2010 79%, 2011
Mean Humidity 82% 80% 96%, 2010 65%, 2012
Minimum Pressure 1029 hPa 22:12 1018 hPa 1034 hPa, 2012 999 hPa, 2013
Maximum Pressure 1034 hPa 09:02 1027 hPa 1036 hPa, 2012 1006 hPa, 2010
Mean Pressure 1032 hPa 1023 hPa 1035 hPa, 2012 1004 hPa, 2010
Mean Wind Speed 2.4 mph (-2.8) 5.3 mph (+0.1) 10.0 mph, 2014 1.7 mph, 2022
Maximum Wind Speed 10.9 mph 22:53 14.0 mph 21.9 mph, 2014 8.1 mph, 2016
Maximum Gust 16.0 mph 21:58 21.1 mph 30.4 mph, 2014 13.2 mph, 2011
Mean Wind Direction NNW
Rainfall 0.0 mm 17.7 mm (70%) 3.8 mm, 2010
Maximum Hourly Rain n/a 1.2, 2014
Maximum 10-min Rain n/a 0.6, 2014
Maximum Rain Rate n/a 3, 2017
Minimum Dew Point 1.0 °C 01:38 1.0 °C 9.0 °C, 2024 -2.9 °C, 2011
Maximum Dew Point 7.0 °C 22:15 5.4 °C 12.0 °C, 2010 2.3 °C, 2018
Mean Dew Point 4.5 °C 3.1 °C 10.7 °C, 2010 -0.5 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 2.9 °C 01:48 3.9 °C 11.0 °C, 2017 0.5 °C, 2018
Day Maximum (09-21) 10.4 °C 17:00 9.2 °C 16.7 °C, 2024 5.8 °C, 2013
Max 10m Temp Rise 0.4 °C 02:10 0.5 °C 1.3 °C, 2009 0.2 °C, 2010
Max 1hr Temp Rise 1.2 °C 02:57 1.4 °C 3.4 °C, 2012 0.5 °C, 2010
Max 1hr Hum Rise 3% 02:04 7% 11%, 2014 3%, 2010
Max 10m Temp Fall 0.7 °C 23:34 0.6 °C 0.7 °C, 2009 0.2 °C, 2019
Max 1hr Temp Fall 1.6 °C 23:51 1.4 °C 2.7 °C, 2022 0.6 °C, 2019
Max 1hr Hum Fall 4% 03:48 8% 20%, 2018 3%, 2010
Max 10m Wind Speed 7.9 mph 21:40 10.4 mph 17.2 mph, 2014 5.8 mph, 2016
Minimum Feels-like -0.3 °C 01:14 0.2 °C 11.4 °C, 2024 -4.0 °C, 2018
Maximum Feels-like 10.4 °C 16:54 9.2 °C 18.4 °C, 2024 4.7 °C, 2013
Mean Feels-like 6.5 °C 4.6 °C 14.4 °C, 2024 1.1 °C, 2018
Air-frost Hrs 0 hrs 0.2 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 7.5 °C (+0.8) 5.5 °C (-0.9) 11.3 °C (+4.6), 2011 3.6 °C (-3.1), 2019
Humidity Range 15% 23% 42%, 2009 6%, 2010
Pressure Range 5 hPa 8 hPa 17 hPa, 2013 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]48 hrs (68%) [23%] 10.9 [100%], 2009 0 [0%], 2010
Wet Hours 023 hrs (67%) [4.8%] 6, 2010 , 2009
Cloud Cover Overcast
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 8.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 20th March 2021.
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 derived based on analysis of webcam observations, but may use data from our closest site, Heathrow, when needed.
Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually.
Rainfall totals may be manually adjusted after the fact to correct delayed or erroneous data.
Cloud cover and Events are manually reported, often with multi-week delays.
Data is generally reliable and accurate but should always be viewed with some quantity of salt to hand.
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Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

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