Daily Report for 15th July 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 14.1 °C (-0.2) 23:58 14.1 °C (+0.3) 17.9 °C (+3.6), 2014 10.7 °C (-3.6), 2024
Maximum Temperature 20.9 °C (-2.2) 09:32 21.6 °C (-1.2) 30.1 °C (+7.0), 2013 18.6 °C (-4.5), 2020
Mean Temperature 18.0 °C (-1.2) 17.6 °C (-0.5) 23.6 °C, 2013 15.2 °C, 2012
Minimum Humidity 71% 14:50 64% 71%, 2021 22%, 2013
Maximum Humidity 86% 05:34 91% 95%, 2010 66%, 2013
Mean Humidity 78% 80% 82%, 2024 41%, 2013
Minimum Pressure 1021 hPa 00:23 1012 hPa 1025 hPa, 2016 999 hPa, 2010
Maximum Pressure 1027 hPa 23:02 1018 hPa 1027 hPa, 2016 1005 hPa, 2023
Mean Pressure 1024 hPa 1015 hPa 1026 hPa, 2016 1002 hPa, 2023
Mean Wind Speed 3.7 mph (-0.6) 3.2 mph (-1.1) 11.2 mph, 2023 0.8 mph, 2024
Maximum Wind Speed 11.3 mph 18:36 10.7 mph 26.0 mph, 2023 5.9 mph, 2013
Maximum Gust 18.2 mph 18:36 15.7 mph 42.6 mph, 2023 7.6 mph, 2013
Mean Wind Direction N
Rainfall 0.0 mm 60.0 mm (270%) 25.0 mm, 2024
Maximum Hourly Rain 0.0 mm 01:06 14.4 mm, 2024
Maximum 10-min Rain n/a 03:22 4.6, 2024
Maximum Rain Rate n/a 01:06 60, 2024
Minimum Dew Point 11.3 °C 23:58 11.8 °C 11.9 °C, 2009 4.2 °C, 2013
Maximum Dew Point 16.0 °C 09:27 15.8 °C 18.4 °C, 2015 11.9 °C, 2011
Mean Dew Point 14.1 °C 13.9 °C 15.4 °C, 2015 8.4 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 14.6 °C * 05:26 14.2 °C 17.9 °C, 2014 10.7 °C, 2024
Day Maximum (09-21) 20.9 °C 09:33 21.6 °C 30.1 °C, 2013 18.6 °C, 2020
Max 10m Temp Rise 0.5 °C 06:06 0.6 °C 1.7 °C, 2009 0.4 °C, 2017
Max 1hr Temp Rise 2.0 °C 06:55 2.1 °C 4.3 °C, 2011 1.0 °C, 2020
Max 1hr Hum Rise 4% 10:36 9% 18%, 2024 3%, 2015
Max 10m Temp Fall 0.3 °C 01:09 0.6 °C 1.6 °C, 2009 0.2 °C, 2017
Max 1hr Temp Fall 1.3 °C 22:51 1.9 °C 2.8 °C, 2018 0.9 °C, 2017
Max 1hr Hum Fall 6% 06:55 10% 20%, 2012 5%, 2020
Max 10m Wind Speed 7.7 mph 18:44 7.6 mph 21.6 mph, 2023 3.6 mph, 2013
Minimum Feels-like 16.0 °C 23:58 16.6 °C 20.7 °C, 2014 11.8 °C, 2024
Maximum Feels-like 25.4 °C 09:32 25.8 °C 32.3 °C, 2018 18.9 °C, 2012
Mean Feels-like 21.5 °C 20.9 °C 25.6 °C, 2018 16.0 °C, 2012
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 (-2.0) 7.5 °C (-1.5) 15.8 °C (+7.0), 2018 4.5 °C (-4.3), 2015
Humidity Range 15% 27% 62%, 2018 15%, 2020
Pressure Range 6 hPa 5 hPa 11 hPa, 2009 2 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 4 [27%]47 hrs (49%) [21%] 14 [95%], 2013 0 [0%], 2017
Wet Hours 026 hrs (158%) [7.2%] 6, 2024 0, 2011
Cloud Cover am: Sunny transitioned to Overcast
pm: Overcast
Events None
Comments -
Extra Comments
Issues rain gauge blocked - still reporting rain from days ago
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 21.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 15th 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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Wind rose