Daily Report for 21st August 2023

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 15.2 °C (+1.3) 06:35 14.4 °C (+0.1) 19.0 °C (+5.1), 2010 7.7 °C (-6.2), 2014
Maximum Temperature 24.3 °C (+2.0) 17:39 22.4 °C (-0.3) 26.0 °C (+3.7), 2018 18.4 °C (-3.9), 2014
Mean Temperature 19.4 °C (+1.7) 18.3 °C (-0.1) 21.7 °C, 2018 13.5 °C, 2014
Minimum Humidity 60% 17:41 63% 79%, 2017 34%, 2013
Maximum Humidity 93% 06:55 93% 93%, 2023 83%, 2020
Mean Humidity 78% 80% 85%, 2010 57%, 2013
Minimum Pressure 1022 hPa 19:34 1012 hPa 1026 hPa, 2019 1000 hPa, 2020
Maximum Pressure 1026 hPa 08:57 1018 hPa 1029 hPa, 2019 1010 hPa, 2020
Mean Pressure 1024 hPa 1015 hPa 1027 hPa, 2019 1004 hPa, 2020
Mean Wind Speed 5.5 mph (+1.5) 5.3 mph (+1.3) 12.4 mph, 2020 0.8 mph, 2021
Maximum Wind Speed 11.8 mph 17:04 13.7 mph 28.6 mph, 2020 5.6 mph, 2021
Maximum Gust 18.4 mph 18:40 20.9 mph 43.8 mph, 2020 9.1 mph, 2021
Mean Wind Direction W
Rainfall 0.0 mm 36.1 mm (99%) 4.3 mm, 2017
Maximum Hourly Rain n/a 1.3, 2017
Maximum 10-min Rain n/a 0.3, 2009
Maximum Rain Rate n/a 3, 2017
Minimum Dew Point 14.0 °C 05:56 12.5 °C 16.8 °C, 2010 4.2 °C, 2014
Maximum Dew Point 16.9 °C 15:35 16.6 °C 18.3 °C, 2010 9.1 °C, 2014
Mean Dew Point 15.3 °C 14.5 °C 17.6 °C, 2010 6.3 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 15.2 °C 06:35 14.5 °C 19.0 °C, 2010 7.7 °C, 2014
Day Maximum (09-21) 24.3 °C 17:40 22.4 °C 26.0 °C, 2018 18.4 °C, 2014
Max 10m Temp Rise 0.6 °C 11:07 0.6 °C 1.1 °C, 2009 0.2 °C, 2017
Max 1hr Temp Rise 2.4 °C 11:25 2.0 °C 3.8 °C, 2009 0.8 °C, 2017
Max 1hr Hum Rise 5% 18:52 9% 18%, 2016 3%, 2017
Max 10m Temp Fall 0.4 °C 18:40 0.5 °C 1.2 °C, 2009 0.1 °C, 2017
Max 1hr Temp Fall 1.5 °C 20:20 1.7 °C 2.7 °C, 2009 0.4 °C, 2017
Max 1hr Hum Fall 9% 11:29 9% 23%, 2009 2%, 2017
Max 10m Wind Speed 9.0 mph 18:53 10.1 mph 19.2 mph, 2020 3.7 mph, 2021
Minimum Feels-like 18.6 °C 06:14 17.1 °C 24.3 °C, 2010 6.0 °C, 2014
Maximum Feels-like 29.3 °C 15:35 27.0 °C 31.2 °C, 2018 18.4 °C, 2014
Mean Feels-like 23.6 °C 22.0 °C 26.5 °C, 2018 13.6 °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 9.1 °C (+0.7) 8.1 °C (-0.4) 14.1 °C (+5.7), 2013 3.1 °C (-5.3), 2010
Humidity Range 33% 31% 50%, 2013 7%, 2017
Pressure Range 4 hPa 7 hPa 12 hPa, 2016 2 hPa, 2022
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 7 [54%]122 hrs (95%) [43%] 11 [85%], 2013 0 [0%], 2017
Wet Hours 035 hrs (136%) [7%] 7, 2017 0, 2010
Cloud Cover unknown
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 21.6 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 21st August 2023.
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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Webcam Summary of Cloud Conditions

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