Daily Report for 19th August 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 15.3 °C (+1.4) 04:51 16.6 °C (+2.3) 17.7 °C (+3.8), 2012 9.1 °C (-4.8), 2011
Maximum Temperature 20.1 °C (-2.3) 23:53 26.7 °C (+3.9) 29.5 °C (+7.1), 2012 18.1 °C (-4.3), 2014
Mean Temperature 18.1 °C (-0.4) 21.4 °C (+3.1) 23.6 °C, 2012 13.8 °C, 2014
Minimum Humidity 85% 00:03 53% 85%, 2020 35%, 2009
Maximum Humidity 95% 20:35 89% 97%, 2011 76%, 2014
Mean Humidity 92% 73% 92%, 2020 56%, 2013
Minimum Pressure 1000 hPa 23:20 1013 hPa 1018 hPa, 2018 1000 hPa, 2020
Maximum Pressure 1011 hPa 00:01 1017 hPa 1026 hPa, 2013 1009 hPa, 2016
Mean Pressure 1005 hPa 1015 hPa 1019 hPa, 2018 1005 hPa, 2020
Mean Wind Speed 3.4 mph (-0.6) 3.6 mph (-0.4) 7.1 mph, 2023 2.6 mph, 2012
Maximum Wind Speed 9.4 mph 14:41 11.6 mph 22.3 mph, 2016 9.2 mph, 2012
Maximum Gust 19.6 mph 12:53 18.2 mph 30.6 mph, 2016 12.5 mph, 2013
Mean Wind Direction S
Rainfall 11.5 mm 37.3 mm (113%) 11.5 mm, 2020
Maximum Hourly Rain 3.5 mm 17:00 3.5 mm, 2020
Maximum 10-min Rain 0.5 mm 16:45 0.9 mm, 2015
Maximum Rain Rate 10 mm/h 16:43 18 mm/h, 2015
Minimum Dew Point 13.9 °C 04:16 13.6 °C 14.6 °C, 2023 4.1 °C, 2014
Maximum Dew Point 19.1 °C 23:53 18.1 °C 19.8 °C, 2012 8.5 °C, 2014
Mean Dew Point 16.8 °C 15.8 °C 16.8 °C, 2020 5.7 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 15.3 °C 04:52 16.9 °C 19.1 °C, 2022 9.1 °C, 2011
Day Maximum (09-21) * 19.4 °C * 20:47 26.7 °C 29.5 °C, 2012 18.1 °C, 2014
Max 10m Temp Rise 0.3 °C 08:25 0.7 °C 0.9 °C, 2012 0.2 °C, 2016
Max 1hr Temp Rise 1.2 °C 08:49 2.6 °C 3.2 °C, 2012 0.7 °C, 2016
Max 1hr Hum Rise 3% 01:01 9% 16%, 2012 3%, 2020
Max 10m Temp Fall 0.3 °C 03:01 0.6 °C 1.0 °C, 2019 0.3 °C, 2020
Max 1hr Temp Fall 1.1 °C 03:41 2.1 °C 2.6 °C, 2013 0.9 °C, 2021
Max 1hr Hum Fall 3% 07:29 11% 17%, 2013 3%, 2020
Max 10m Wind Speed 7.6 mph 12:27 8.3 mph 16.2 mph, 2016 6.7 mph, 2012
Minimum Feels-like 18.7 °C 04:28 20.2 °C 22.3 °C, 2012 7.9 °C, 2011
Maximum Feels-like 26.9 °C 23:48 32.0 °C 34.7 °C, 2012 18.1 °C, 2014
Mean Feels-like 23.4 °C 26.1 °C 28.7 °C, 2012 13.8 °C, 2014
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 4.8 °C (-3.6) 10.1 °C (+1.6) 14.6 °C (+6.2), 2009 3.1 °C (-5.3), 2016
Humidity Range 10% 36% 52%, 2009 9%, 2016
Pressure Range 10 hPa 4 hPa 14 hPa, 2013 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]115 hrs (99%) [45%] 10.5 [80%], 2009 0 [0%], 2020
Wet Hours 8
[Mean rain rate: 1.4 mm/h]		23 hrs (97%) [5%] 8, 2020 0, 2009
Cloud Cover Overcast
Events None
Comments day Rain
Extra Comments
Issues Rain gauge blocked, no data. Backfilled from St James
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 21.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 19th August 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

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