Daily Report for 15th August 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 16.8 °C (+2.6) 07:21 16.8 °C (+2.5) 17.9 °C (+3.7), 2022 11.5 °C (-2.7), 2016
Maximum Temperature 20.4 °C (-2.1) 17:49 27.8 °C (+4.9) 29.2 °C (+6.7), 2022 19.9 °C (-2.6), 2015
Mean Temperature 18.5 °C (+0.3) 22.1 °C (+3.7) 23.3 °C, 2022 15.8 °C, 2014
Minimum Humidity 90% 17:27 49% 90%, 2020 39%, 2022
Maximum Humidity 95% 03:56 87% 97%, 2010 76%, 2011
Mean Humidity 93% 69% 93%, 2020 58%, 2017
Minimum Pressure 1014 hPa 23:43 1015 hPa 1022 hPa, 2016 1002 hPa, 2012
Maximum Pressure 1016 hPa 00:02 1018 hPa 1025 hPa, 2016 1007 hPa, 2022
Mean Pressure 1016 hPa 1016 hPa 1023 hPa, 2016 1004 hPa, 2022
Mean Wind Speed 2.0 mph (-2.0) 3.7 mph (-0.3) 6.9 mph, 2019 2.0 mph, 2020
Maximum Wind Speed 8.3 mph 08:31 11.4 mph 18.4 mph, 2024 8.3 mph, 2020
Maximum Gust 13.8 mph 08:48 17.7 mph 27.6 mph, 2019 11.8 mph, 2014
Mean Wind Direction NNE
Rainfall 6.9 mm 9.7 mm (37%) 9.1 mm, 2022
Maximum Hourly Rain 4.0 mm 19:44 9.1 mm, 2022
Maximum 10-min Rain 2.0 mm 19:32 7.0 mm, 2022
Maximum Rain Rate 40 mm/h 19:30 114 mm/h, 2022
Minimum Dew Point 15.9 °C 08:49 13.4 °C 15.9 °C, 2020 5.7 °C, 2015
Maximum Dew Point 19.0 °C 20:10 18.0 °C 19.0 °C, 2020 11.5 °C, 2011
Mean Dew Point 17.3 °C 15.6 °C 17.3 °C, 2020 8.7 °C, 2011
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 16.8 °C 07:22 17.0 °C 18.3 °C, 2022 11.5 °C, 2016
Day Maximum (09-21) 20.4 °C 18:08 27.8 °C 29.2 °C, 2022 19.9 °C, 2015
Max 10m Temp Rise 0.2 °C 09:24 0.7 °C 0.8 °C, 2011 0.2 °C, 2020
Max 1hr Temp Rise 0.8 °C 11:02 2.8 °C 3.5 °C, 2016 0.8 °C, 2020
Max 1hr Hum Rise 3% 19:33 9% 29%, 2022 3%, 2020
Max 10m Temp Fall 0.2 °C 04:21 0.6 °C 1.4 °C, 2022 0.2 °C, 2020
Max 1hr Temp Fall 0.4 °C 05:10 2.1 °C 4.8 °C, 2022 0.4 °C, 2020
Max 1hr Hum Fall 3% 11:06 11% 16%, 2015 3%, 2020
Max 10m Wind Speed 5.1 mph 08:54 8.0 mph 14.5 mph, 2024 5.1 mph, 2020
Minimum Feels-like 21.4 °C 06:41 20.5 °C 21.4 °C, 2020 11.6 °C, 2015
Maximum Feels-like 27.1 °C 19:10 32.9 °C 33.2 °C, 2022 21.2 °C, 2015
Mean Feels-like 24.0 °C 26.6 °C 27.4 °C, 2022 17.4 °C, 2015
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.6 °C (-4.7) 11.0 °C (+2.4) 11.6 °C (+3.3), 2016 3.6 °C (-4.7), 2020
Humidity Range 5% 39% 53%, 2022 5%, 2020
Pressure Range 2 hPa 3 hPa 11 hPa, 2014 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]108 hrs (117%) [53%] 13 [98%], 2016 0 [0%], 2020
Wet Hours 3
[Mean rain rate: 2.3 mm/h]		11 hrs (61%) [3.1%] 3, 2020 0, 2009
Cloud Cover Overcast
Events Thunder
Comments o.night Rain, Very Heavy 19 Shower
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 22.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 15th 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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