Daily Report for 28th July 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.7 °C (-1.0) 23:54 14.8 °C (+0.6) 16.9 °C (+2.2), 2018 11.6 °C (-3.1), 2024
Maximum Temperature 20.5 °C (-2.8) 13:46 23.7 °C (+0.6) 26.6 °C (+3.3), 2024 19.1 °C (-4.2), 2015
Mean Temperature 17.1 °C (-1.9) 19.0 °C (+0.6) 19.8 °C, 2024 16.1 °C, 2015
Minimum Humidity 65% 13:51 61% 65%, 2021 34%, 2012
Maximum Humidity 90% 14:49 91% 93%, 2024 68%, 2012
Mean Humidity 83% 78% 83%, 2021 51%, 2012
Minimum Pressure 1007 hPa 03:39 1014 hPa 1022 hPa, 2024 1002 hPa, 2013
Maximum Pressure 1009 hPa 23:54 1019 hPa 1028 hPa, 2024 1008 hPa, 2013
Mean Pressure 1008 hPa 1017 hPa 1026 hPa, 2024 1006 hPa, 2015
Mean Wind Speed 6.0 mph (+1.7) 2.8 mph (-1.5) 10.0 mph, 2018 0.9 mph, 2024
Maximum Wind Speed 16.2 mph 13:54 10.5 mph 21.4 mph, 2018 6.7 mph, 2011
Maximum Gust 22.8 mph 13:54 15.6 mph 39.2 mph, 2018 10.0 mph, 2011
Mean Wind Direction WSW
Rainfall 10.8 mm 116.1 mm (279%) 10.8 mm, 2021
Maximum Hourly Rain 7.7 mm 14:37 7.7 mm, 2021
Maximum 10-min Rain 2.6 mm 14:01 2.6 mm, 2021
Maximum Rain Rate 30 mm/h 13:56 30 mm/h, 2021
Minimum Dew Point 11.0 °C 23:54 12.5 °C 14.5 °C, 2023 2.3 °C, 2012
Maximum Dew Point 15.4 °C 02:15 17.0 °C 17.6 °C, 2023 10.0 °C, 2012
Mean Dew Point 14.1 °C 14.9 °C 15.8 °C, 2023 6.9 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 16.9 °C * 06:08 15.0 °C 17.2 °C, 2018 11.6 °C, 2024
Day Maximum (09-21) 20.5 °C 13:46 23.7 °C 26.6 °C, 2024 19.1 °C, 2015
Max 10m Temp Rise 0.8 °C 12:00 0.6 °C 1.1 °C, 2009 0.5 °C, 2011
Max 1hr Temp Rise 2.1 °C 09:47 2.2 °C 4.3 °C, 2024 1.4 °C, 2015
Max 1hr Hum Rise 25% 14:51 11% 25%, 2021 6%, 2009
Max 10m Temp Fall 2.2 °C 14:01 0.7 °C 2.2 °C, 2021 0.4 °C, 2009
Max 1hr Temp Fall 4.7 °C 14:40 2.2 °C 4.7 °C, 2021 1.4 °C, 2016
Max 1hr Hum Fall 13% 19:34 10% 16%, 2018 7%, 2019
Max 10m Wind Speed 12.5 mph 17:13 7.5 mph 18.6 mph, 2018 4.7 mph, 2024
Minimum Feels-like 15.5 °C 23:50 17.6 °C 20.1 °C, 2023 12.9 °C, 2024
Maximum Feels-like 24.0 °C 12:21 28.7 °C 30.6 °C, 2024 19.5 °C, 2015
Mean Feels-like 20.6 °C 23.0 °C 23.6 °C, 2023 16.8 °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 6.8 °C (-1.8) 8.9 °C (+0.0) 15.0 °C (+6.5), 2024 5.4 °C (-3.1), 2015
Humidity Range 25% 30% 48%, 2018 25%, 2021
Pressure Range 2 hPa 5 hPa 11 hPa, 2020 2 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [14%]152 hrs (86%) [37%] 11 [77%], 2024 0.3 [2%], 2019
Wet Hours 3
[Mean rain rate: 3.6 mm/h]		40 hrs (131%) [6%] 3, 2021 0, 2009
Cloud Cover Mostly Cloudy with periods of Partly Cloudy
Events None
Comments Heavy shs
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 21.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 28th July 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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