Daily Report for 12th August 2019

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.9 °C (-2.4) 23:46 15.2 °C (+0.8) 21.1 °C (+6.8), 2020 11.9 °C (-2.4), 2019
Maximum Temperature 18.8 °C (-4.0) 11:45 23.6 °C (+0.5) 33.9 °C (+11.1), 2020 18.8 °C (-4.0), 2019
Mean Temperature 15.2 °C (-3.2) 19.2 °C (+0.6) 26.5 °C, 2020 15.2 °C, 2019
Minimum Humidity 62% 11:41 55% 72%, 2021 30%, 2022
Maximum Humidity 91% 23:02 89% 93%, 2024 73%, 2013
Mean Humidity 81% 74% 86%, 2009 53%, 2022
Minimum Pressure 1014 hPa 00:04 1010 hPa 1021 hPa, 2015 1005 hPa, 2014
Maximum Pressure 1018 hPa 23:48 1015 hPa 1024 hPa, 2015 1009 hPa, 2014
Mean Pressure 1015 hPa 1012 hPa 1023 hPa, 2016 1007 hPa, 2014
Mean Wind Speed 1.7 mph (-2.3) 5.6 mph (+1.6) 8.3 mph, 2016 1.7 mph, 2019
Maximum Wind Speed 11.2 mph 12:31 14.0 mph 20.6 mph, 2016 9.2 mph, 2010
Maximum Gust 15.0 mph 12:30 23.2 mph 37.1 mph, 2016 12.8 mph, 2011
Mean Wind Direction NW
Rainfall 4.0 mm 14.1 mm (67%) 4.0 mm, 2019
Maximum Hourly Rain 3.7 mm 16:08 3.7 mm, 2019
Maximum 10-min Rain 3.3 mm 15:56 3.3 mm, 2019
Maximum Rain Rate 40 mm/h 15:49 40 mm/h, 2019
Minimum Dew Point 9.5 °C 23:59 12.5 °C 17.6 °C, 2020 4.2 °C, 2013
Maximum Dew Point 13.4 °C 17:45 16.2 °C 24.2 °C, 2024 11.2 °C, 2014
Mean Dew Point 11.8 °C 14.2 °C 19.7 °C, 2024 7.6 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 13.3 °C * 05:00 15.4 °C 21.1 °C, 2020 12.4 °C, 2014
Day Maximum (09-21) 18.8 °C 11:45 23.6 °C 33.9 °C, 2020 18.8 °C, 2019
Max 10m Temp Rise 0.6 °C 10:35 0.7 °C 0.9 °C, 2013 0.4 °C, 2009
Max 1hr Temp Rise 2.3 °C 11:04 2.3 °C 3.0 °C, 2024 1.2 °C, 2010
Max 1hr Hum Rise 14% 13:00 13% 15%, 2018 4%, 2017
Max 10m Temp Fall 0.8 °C 12:37 0.8 °C 1.1 °C, 2014 0.3 °C, 2015
Max 1hr Temp Fall 2.3 °C 12:59 2.1 °C 2.8 °C, 2016 1.0 °C, 2009
Max 1hr Hum Fall 13% 08:55 12% 16%, 2018 6%, 2009
Max 10m Wind Speed 6.9 mph 12:38 10.7 mph 15.6 mph, 2016 6.8 mph, 2011
Minimum Feels-like 13.0 °C 23:50 17.9 °C 27.2 °C, 2020 13.0 °C, 2019
Maximum Feels-like 21.1 °C 11:57 27.4 °C 44.5 °C, 2024 20.1 °C, 2014
Mean Feels-like 17.4 °C 22.7 °C 33.4 °C, 2020 16.5 °C, 2014
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 6.9 °C (-1.5) 8.4 °C (-0.2) 14.9 °C (+6.5), 2024 4.9 °C (-3.5), 2021
Humidity Range 29% 34% 53%, 2016 18%, 2021
Pressure Range 4 hPa 5 hPa 10 hPa, 2018 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 1.5 [11%]53 hrs (71%) [32%] 13.5 [100%], 2016 0.4 [3%], 2018
Wet Hours 1
[Mean rain rate: 4.0 mm/h]		9 hrs (61%) [3.1%] 4, 2015 0, 2011
Cloud Cover Mostly Cloudy with periods of Partly Cloudy
Events None
Comments pm Heavy Showers
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 12th August 2019.
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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