Daily Report for 9th August 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.6 °C (-0.8) 03:22 13.2 °C (-1.3) 17.4 °C (+3.0), 2019 10.7 °C (-3.7), 2023
Maximum Temperature 21.7 °C (-1.3) 14:31 21.1 °C (-2.1) 31.7 °C (+8.7), 2020 15.4 °C (-7.6), 2017
Mean Temperature 16.0 °C (-1.0) 16.6 °C (-1.7) 23.7 °C, 2020 13.9 °C, 2017
Minimum Humidity 61% 14:13 62% 78%, 2017 30%, 2015
Maximum Humidity 94% 09:18 93% 98%, 2023 71%, 2011
Mean Humidity 86% 81% 86%, 2021 52%, 2016
Minimum Pressure 1011 hPa 05:05 1006 hPa 1029 hPa, 2022 999 hPa, 2019
Maximum Pressure 1015 hPa 23:30 1012 hPa 1032 hPa, 2022 1008 hPa, 2019
Mean Pressure 1013 hPa 1009 hPa 1030 hPa, 2022 1002 hPa, 2019
Mean Wind Speed 4.6 mph (+0.6) 4.0 mph (+0.0) 7.9 mph, 2019 1.7 mph, 2022
Maximum Wind Speed 13.8 mph 12:13 12.1 mph 20.5 mph, 2019 7.4 mph, 2012
Maximum Gust 21.7 mph 12:44 18.7 mph 36.9 mph, 2019 8.7 mph, 2012
Mean Wind Direction WSW
Rainfall 9.6 mm 30.7 mm (196%) 39.1 mm, 2017
Maximum Hourly Rain 5.0 mm 17:31 11.2 mm, 2017
Maximum 10-min Rain 2.0 mm 16:51 4.8 mm, 2019
Maximum Rain Rate 30 mm/h 16:43 79 mm/h, 2019
Minimum Dew Point 11.6 °C 02:07 11.1 °C 15.2 °C, 2019 3.3 °C, 2016
Maximum Dew Point 15.6 °C 15:48 15.1 °C 20.2 °C, 2020 8.3 °C, 2016
Mean Dew Point 13.5 °C 13.1 °C 17.2 °C, 2020 5.5 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.6 °C 04:48 13.5 °C 18.4 °C, 2019 10.7 °C, 2023
Day Maximum (09-21) 21.7 °C 14:32 21.1 °C 31.7 °C, 2020 15.4 °C, 2017
Max 10m Temp Rise 0.7 °C 12:25 0.7 °C 1.1 °C, 2012 0.2 °C, 2017
Max 1hr Temp Rise 2.4 °C 11:51 2.3 °C 5.0 °C, 2012 0.6 °C, 2018
Max 1hr Hum Rise 13% 17:16 12% 20%, 2019 2%, 2017
Max 10m Temp Fall 1.1 °C 16:48 0.7 °C 1.5 °C, 2019 0.2 °C, 2017
Max 1hr Temp Fall 3.8 °C 17:04 1.9 °C 3.8 °C, 2019 0.8 °C, 2017
Max 1hr Hum Fall 14% 12:00 12% 18%, 2014 1%, 2017
Max 10m Wind Speed 11.0 mph 12:48 9.3 mph 16.4 mph, 2019 4.8 mph, 2009
Minimum Feels-like 15.7 °C 02:29 15.0 °C 21.5 °C, 2019 11.5 °C, 2016
Maximum Feels-like 25.3 °C 14:35 24.5 °C 38.9 °C, 2020 18.3 °C, 2017
Mean Feels-like 19.0 °C 19.5 °C 29.1 °C, 2020 15.7 °C, 2017
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 8.1 °C (-0.5) 7.9 °C (-0.8) 14.8 °C (+6.2), 2020 2.3 °C (-6.3), 2017
Humidity Range 33% 31% 57%, 2012 8%, 2017
Pressure Range 5 hPa 6 hPa 13 hPa, 2017 3 hPa, 2022
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [15%]29 hrs (51%) [23%] 13 [95%], 2022 0 [0%], 2017
Wet Hours 7
[Mean rain rate: 1.4 mm/h]
24 hrs (213%) [11%] 16, 2017 0, 2009
Cloud Cover am: Overcast
pm: Partly Cloudy transitioned to Mostly Cloudy
Events None
Comments rn
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 18.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 9th 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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