Daily Report for 17th June 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 16.1 °C (+4.0) 23:52 14.2 °C (+2.6) 16.4 °C (+4.3), 2022 8.3 °C (-3.8), 2010
Maximum Temperature 21.3 °C (+0.2) 14:42 24.8 °C (+4.4) 31.9 °C (+10.8), 2022 14.8 °C (-6.3), 2011
Mean Temperature 19.0 °C (+2.1) 19.7 °C (+3.5) 25.1 °C, 2022 12.5 °C, 2011
Minimum Humidity 76% 15:00 49% 76%, 2021 35%, 2010
Maximum Humidity 94% 23:57 87% 95%, 2011 77%, 2015
Mean Humidity 88% 69% 88%, 2021 54%, 2022
Minimum Pressure 1009 hPa 05:13 1019 hPa 1026 hPa, 2014 995 hPa, 2011
Maximum Pressure 1016 hPa 22:24 1023 hPa 1029 hPa, 2025 1011 hPa, 2011
Mean Pressure 1012 hPa 1021 hPa 1027 hPa, 2014 1003 hPa, 2011
Mean Wind Speed 2.2 mph (-2.2) 2.7 mph (-1.7) 7.1 mph, 2015 1.3 mph, 2020
Maximum Wind Speed 7.6 mph 18:46 10.0 mph 17.0 mph, 2019 7.6 mph, 2021
Maximum Gust 12.5 mph 18:29 15.4 mph 26.6 mph, 2015 11.5 mph, 2017
Mean Wind Direction NNE
Rainfall 3.8 mm 17.0 mm (64%) 7.6 mm, 2011
Maximum Hourly Rain 2.7 mm 20:31 5.5 mm, 2016
Maximum 10-min Rain 0.9 mm 19:53 3.1 mm, 2016
Maximum Rain Rate 7 mm/h 19:46 54 mm/h, 2016
Minimum Dew Point 15.0 °C 23:52 10.6 °C 15.0 °C, 2021 3.8 °C, 2014
Maximum Dew Point 18.5 °C 00:01 16.1 °C 18.5 °C, 2021 9.6 °C, 2014
Mean Dew Point 16.9 °C 13.5 °C 16.9 °C, 2021 8.0 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 18.0 °C * 08:44 14.4 °C 18.0 °C, 2021 8.3 °C, 2010
Day Maximum (09-21) 21.3 °C 14:46 24.7 °C 31.9 °C, 2022 14.8 °C, 2011
Max 10m Temp Rise 0.6 °C 12:01 0.6 °C 0.9 °C, 2022 0.3 °C, 2011
Max 1hr Temp Rise 1.9 °C 12:24 2.3 °C 3.8 °C, 2022 1.2 °C, 2011
Max 1hr Hum Rise 9% 20:13 9% 23%, 2024 7%, 2011
Max 10m Temp Fall 0.4 °C 19:54 0.6 °C 0.8 °C, 2016 0.3 °C, 2013
Max 1hr Temp Fall 1.6 °C 20:39 1.9 °C 2.4 °C, 2017 1.1 °C, 2013
Max 1hr Hum Fall 9% 12:41 12% 23%, 2022 7%, 2009
Max 10m Wind Speed 5.9 mph 18:44 7.5 mph 14.0 mph, 2022 5.5 mph, 2020
Minimum Feels-like 20.1 °C 23:52 16.3 °C 20.1 °C, 2021 6.9 °C, 2010
Maximum Feels-like 27.2 °C 14:40 28.6 °C 37.5 °C, 2022 16.2 °C, 2011
Mean Feels-like 24.2 °C 22.9 °C 29.0 °C, 2022 13.8 °C, 2011
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.2 °C (-3.8) 10.6 °C (+1.7) 15.5 °C (+6.5), 2022 4.9 °C (-4.1), 2011
Humidity Range 18% 38% 50%, 2010 18%, 2021
Pressure Range 7 hPa 4 hPa 16 hPa, 2011 2 hPa, 2020
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.1 [1%]144 hrs (132%) [57%] 13.7 [91%], 2025 0.1 [1%], 2021
Wet Hours 5
[Mean rain rate: 0.8 mm/h]		16 hrs (76%) [3.9%] 7, 2011 0, 2010
Cloud Cover Overcast
Events None
Comments bits of day rain, late rain
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 20.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 17th June 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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