Daily Report for 21st April 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 8.4 °C (+2.1) 06:27 6.1 °C (+0.3) 11.6 °C (+5.3), 2011 0.2 °C (-6.1), 2013
Maximum Temperature 17.6 °C (+2.7) 14:24 17.5 °C (+3.4) 24.4 °C (+9.5), 2011 11.1 °C (-3.8), 2024
Mean Temperature 12.9 °C (+2.4) 11.8 °C (+1.8) 17.5 °C, 2011 7.6 °C, 2024
Minimum Humidity 39% 14:07 44% 68%, 2023 29%, 2019
Maximum Humidity 75% 23:54 85% 98%, 2014 66%, 2011
Mean Humidity 58% 65% 85%, 2023 48%, 2011
Minimum Pressure 1017 hPa 05:01 1019 hPa 1032 hPa, 2015 994 hPa, 2012
Maximum Pressure 1020 hPa 23:50 1025 hPa 1034 hPa, 2015 1002 hPa, 2012
Mean Pressure 1018 hPa 1021 hPa 1033 hPa, 2015 998 hPa, 2012
Mean Wind Speed 7.9 mph (+3.0) 4.8 mph (-0.1) 7.9 mph, 2020 1.9 mph, 2009
Maximum Wind Speed 18.0 mph 13:16 13.4 mph 18.0 mph, 2020 9.4 mph, 2010
Maximum Gust 30.0 mph 12:37 20.0 mph 30.0 mph, 2020 12.7 mph, 2018
Mean Wind Direction ENE
Rainfall 0.0 mm 2.8 mm (10%) 4.4 mm, 2014
Maximum Hourly Rain n/a 2.2, 2014
Maximum 10-min Rain n/a 0.9, 2014
Maximum Rain Rate n/a 10.8, 2014
Minimum Dew Point 2.9 °C 16:51 2.4 °C 8.7 °C, 2018 -3.7 °C, 2010
Maximum Dew Point 6.0 °C 23:10 7.8 °C 14.1 °C, 2018 0.7 °C, 2010
Mean Dew Point 4.5 °C 5.0 °C 11.2 °C, 2018 -1.6 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 8.4 °C 06:20 6.5 °C 11.6 °C, 2011 0.2 °C, 2013
Day Maximum (09-21) 17.6 °C 14:24 17.4 °C 24.4 °C, 2011 11.1 °C, 2024
Max 10m Temp Rise 0.5 °C 08:08 0.7 °C 1.4 °C, 2013 0.4 °C, 2017
Max 1hr Temp Rise 1.9 °C 08:58 2.9 °C 5.7 °C, 2013 1.3 °C, 2017
Max 1hr Hum Rise 9% 20:12 10% 20%, 2014 4%, 2017
Max 10m Temp Fall 0.4 °C 15:37 0.6 °C 1.0 °C, 2025 0.3 °C, 2019
Max 1hr Temp Fall 1.5 °C 20:32 2.0 °C 2.9 °C, 2014 1.5 °C, 2017
Max 1hr Hum Fall 10% 10:37 12% 25%, 2014 8%, 2010
Max 10m Wind Speed 13.3 mph 13:17 10.0 mph 13.3 mph, 2020 6.9 mph, 2018
Minimum Feels-like 5.1 °C 05:53 4.2 °C 11.7 °C, 2018 -0.9 °C, 2013
Maximum Feels-like 17.6 °C 14:22 17.8 °C 26.2 °C, 2018 11.1 °C, 2024
Mean Feels-like 12.4 °C 11.4 °C 18.8 °C, 2018 5.5 °C, 2024
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 9.2 °C (+0.6) 11.3 °C (+3.1) 16.2 °C (+7.6), 2019 5.4 °C (-3.2), 2023
Humidity Range 36% 40% 58%, 2014 24%, 2023
Pressure Range 3 hPa 6 hPa 14 hPa, 2019 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 13 [101%]172 hrs (155%) [66%] 13 [101%], 2019 0 [0%], 2017
Wet Hours 03.5 hrs (11%) [0.7%] 4, 2014 0, 2009
Cloud Cover Sunny
Events Maximum possible sunshine
Comments -
Extra Comments
Issues no pond temp due to covid
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 5.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 21st April 2020.
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

daycamsumFull resolution individual images at up-to 5 minute intervals

Wind rose