Daily Report for 11th August 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.8 °C (-0.6) 06:17 13.3 °C (-1.2) 20.2 °C (+5.8), 2020 8.0 °C (-6.4), 2018
Maximum Temperature 23.9 °C (+1.1) 14:45 21.5 °C (-1.6) 33.4 °C (+10.6), 2020 20.7 °C (-2.1), 2014
Mean Temperature 18.9 °C (+0.3) 17.0 °C (-1.4) 26.9 °C, 2020 15.8 °C, 2018
Minimum Humidity 57% 14:25 61% 67%, 2011 34%, 2022
Maximum Humidity 88% 06:43 92% 97%, 2010 74%, 2013
Mean Humidity 72% 80% 78%, 2011 55%, 2013
Minimum Pressure 1018 hPa 18:31 1008 hPa 1021 hPa, 2022 1004 hPa, 2014
Maximum Pressure 1020 hPa 09:51 1013 hPa 1026 hPa, 2012 1009 hPa, 2014
Mean Pressure 1019 hPa 1011 hPa 1023 hPa, 2022 1007 hPa, 2014
Mean Wind Speed 3.8 mph (-0.2) 4.0 mph (+0.0) 8.1 mph, 2019 0.8 mph, 2015
Maximum Wind Speed 11.7 mph 14:00 12.0 mph 19.4 mph, 2016 5.9 mph, 2015
Maximum Gust 17.1 mph 10:34 18.5 mph 30.0 mph, 2019 7.8 mph, 2015
Mean Wind Direction WSW
Rainfall 0.0 mm 30.9 mm (161%) 7.3 mm, 2014
Maximum Hourly Rain n/a 5.6, 2014
Maximum 10-min Rain n/a 3, 2014
Maximum Rain Rate n/a 90, 2014
Minimum Dew Point 11.7 °C 06:05 11.3 °C 17.5 °C, 2020 5.7 °C, 2013
Maximum Dew Point 15.9 °C 15:48 15.2 °C 20.6 °C, 2020 13.0 °C, 2017
Mean Dew Point 13.6 °C 13.3 °C 18.8 °C, 2020 9.1 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.8 °C 06:18 13.5 °C 20.2 °C, 2020 8.0 °C, 2018
Day Maximum (09-21) 23.9 °C 14:45 21.5 °C 33.4 °C, 2020 20.7 °C, 2014
Max 10m Temp Rise 0.6 °C 08:38 0.7 °C 1.2 °C, 2020 0.4 °C, 2011
Max 1hr Temp Rise 2.9 °C 09:17 2.4 °C 4.7 °C, 2020 1.5 °C, 2011
Max 1hr Hum Rise 6% 21:45 11% 22%, 2014 6%, 2011
Max 10m Temp Fall 0.4 °C 19:56 0.6 °C 2.3 °C, 2014 0.3 °C, 2012
Max 1hr Temp Fall 1.7 °C 20:21 1.9 °C 4.9 °C, 2014 1.0 °C, 2016
Max 1hr Hum Fall 11% 10:04 11% 19%, 2012 7%, 2015
Max 10m Wind Speed 8.1 mph 19:16 9.1 mph 14.8 mph, 2016 3.7 mph, 2015
Minimum Feels-like 15.9 °C 06:02 15.2 °C 25.9 °C, 2020 6.5 °C, 2018
Maximum Feels-like 28.3 °C 14:46 25.1 °C 40.8 °C, 2020 21.6 °C, 2014
Mean Feels-like 22.1 °C 20.0 °C 33.5 °C, 2020 17.3 °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 10.1 °C (+1.6) 8.2 °C (-0.4) 16.0 °C (+7.5), 2022 6.6 °C (-1.9), 2011
Humidity Range 31% 31% 56%, 2022 22%, 2011
Pressure Range 2 hPa 5 hPa 11 hPa, 2012 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 10 [74%]46 hrs (67%) [30%] 13 [96%], 2022 0.1 [1%], 2015
Wet Hours 024 hrs (178%) [9.1%] 3, 2014 0, 2009
Cloud Cover Sunny with periods of Mostly Sunny
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 18.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 11th August 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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