Daily Report for 27th July 2020

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 15.8 °C (+1.1) 04:22 13.5 °C (-0.8) 19.3 °C (+4.6), 2018 12.4 °C (-2.3), 2009
Maximum Temperature 20.2 °C (-3.1) 19:14 21.9 °C (-1.2) 31.8 °C (+8.5), 2018 19.7 °C (-3.6), 2015
Mean Temperature 17.5 °C (-1.0) 17.7 °C (-1.0) 24.5 °C, 2018 16.2 °C, 2009
Minimum Humidity 76% 11:44 55% 83%, 2023 36%, 2013
Maximum Humidity 89% 15:46 87% 96%, 2023 77%, 2014
Mean Humidity 85% 72% 90%, 2023 57%, 2014
Minimum Pressure 1005 hPa 16:10 1015 hPa 1020 hPa, 2022 996 hPa, 2015
Maximum Pressure 1014 hPa 00:02 1021 hPa 1023 hPa, 2022 1004 hPa, 2015
Mean Pressure 1009 hPa 1018 hPa 1022 hPa, 2022 1000 hPa, 2015
Mean Wind Speed 7.1 mph (+2.8) 5.0 mph (+0.7) 8.7 mph, 2015 2.0 mph, 2012
Maximum Wind Speed 18.5 mph 12:13 13.6 mph 19.0 mph, 2015 7.4 mph, 2014
Maximum Gust 31.1 mph 14:46 21.3 mph 31.1 mph, 2020 10.7 mph, 2014
Mean Wind Direction SSW
Rainfall 1.7 mm 36.4 mm (91%) 11.0 mm, 2019
Maximum Hourly Rain 0.5 mm 09:36 5.9 mm, 2018
Maximum 10-min Rain 0.3 mm 09:36 5.1 mm, 2018
Maximum Rain Rate n/a 66, 2018
Minimum Dew Point 12.9 °C 23:47 10.0 °C 15.1 °C, 2018 7.4 °C, 2009
Maximum Dew Point 17.1 °C 20:05 14.3 °C 20.9 °C, 2018 12.9 °C, 2011
Mean Dew Point 14.9 °C 12.2 °C 17.1 °C, 2023 11.0 °C, 2025
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 15.8 °C 04:27 13.7 °C 19.3 °C, 2018 12.4 °C, 2009
Day Maximum (09-21) 20.2 °C 18:53 21.9 °C 31.8 °C, 2018 19.2 °C, 2019
Max 10m Temp Rise 0.5 °C 10:41 0.6 °C 0.8 °C, 2017 0.2 °C, 2019
Max 1hr Temp Rise 2.1 °C 11:19 2.2 °C 3.4 °C, 2018 0.8 °C, 2019
Max 1hr Hum Rise 7% 13:01 11% 20%, 2018 3%, 2023
Max 10m Temp Fall 0.4 °C 23:05 0.6 °C 1.4 °C, 2018 0.3 °C, 2015
Max 1hr Temp Fall 1.4 °C 23:53 2.1 °C 5.0 °C, 2018 0.8 °C, 2023
Max 1hr Hum Fall 10% 11:29 10% 16%, 2018 5%, 2019
Max 10m Wind Speed 12.8 mph 15:34 9.8 mph 14.0 mph, 2015 3.9 mph, 2009
Minimum Feels-like 18.9 °C 04:10 15.0 °C 23.4 °C, 2018 14.2 °C, 2024
Maximum Feels-like 25.5 °C 19:59 24.7 °C 37.8 °C, 2018 22.6 °C, 2011
Mean Feels-like 21.4 °C 20.2 °C 29.5 °C, 2018 18.8 °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 4.4 °C (-4.2) 8.4 °C (-0.4) 14.2 °C (+5.6), 2013 4.4 °C (-4.2), 2020
Humidity Range 13% 32% 54%, 2013 13%, 2020
Pressure Range 10 hPa 5 hPa 14 hPa, 2024 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.2 [1%]133 hrs (78%) [33%] 10 [70%], 2024 0 [0%], 2019
Wet Hours 4
[Mean rain rate: 0.4 mm/h]		48 hrs (162%) [7.4%] 9, 2019 0, 2011
Cloud Cover Overcast with periods of Mostly Cloudy
Events None
Comments Rain spells
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 17.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 27th July 2020.
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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