Daily Report for 23rd August 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.7 °C (-0.1) 10:32 13.6 °C (-0.7) 18.2 °C (+4.4), 2022 9.3 °C (-4.4), 2014
Maximum Temperature 16.4 °C (-5.7) 00:13 22.0 °C (-0.7) 29.6 °C (+7.5), 2016 16.4 °C (-5.7), 2011
Mean Temperature 15.0 °C (-2.9) 17.7 °C (-0.7) 22.3 °C, 2016 14.2 °C, 2014
Minimum Humidity 73% 00:00 49% 73%, 2011 33%, 2016
Maximum Humidity 95% 23:59 85% 96%, 2010 74%, 2009
Mean Humidity 88% 69% 88%, 2011 57%, 2014
Minimum Pressure 1011 hPa 14:09 1010 hPa 1026 hPa, 2021 997 hPa, 2010
Maximum Pressure 1018 hPa 00:38 1016 hPa 1031 hPa, 2021 1006 hPa, 2010
Mean Pressure 1014 hPa 1013 hPa 1029 hPa, 2021 1002 hPa, 2010
Mean Wind Speed 3.4 mph (-0.6) 4.5 mph (+0.5) 7.5 mph, 2024 1.9 mph, 2019
Maximum Wind Speed 11.8 mph 12.3 mph 22.5 mph, 2010 8.3 mph, 2019
Maximum Gust 17.0 mph 02:09 17.6 mph 30.0 mph, 2010 11.5 mph, 2019
Mean Wind Direction NNE
Rainfall 9.8 mm 53.6 mm (134%) 21.0 mm, 2010
Maximum Hourly Rain 5.5 mm 10:42 5.8 mm, 2015
Maximum 10-min Rain 1.9 mm 10:59 3.4 mm, 2015
Maximum Rain Rate 30 mm/h 10:54 54 mm/h, 2015
Minimum Dew Point 11.5 °C 03:48 8.7 °C 16.8 °C, 2022 2.7 °C, 2014
Maximum Dew Point 14.8 °C 14:52 14.0 °C 19.9 °C, 2022 8.1 °C, 2014
Mean Dew Point 13.0 °C 11.4 °C 18.2 °C, 2022 5.4 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.7 °C 10:31 13.7 °C 18.6 °C, 2018 9.3 °C, 2014
Day Maximum (09-21) * 15.6 °C * 14:50 22.0 °C 29.6 °C, 2016 15.6 °C, 2011
Max 10m Temp Rise 0.2 °C 13:13 0.6 °C 0.8 °C, 2016 0.2 °C, 2011
Max 1hr Temp Rise 0.7 °C 13:33 2.3 °C 4.1 °C, 2016 0.7 °C, 2011
Max 1hr Hum Rise 6% 08:48 9% 13%, 2012 4%, 2017
Max 10m Temp Fall 0.5 °C 01:37 0.5 °C 1.0 °C, 2014 0.3 °C, 2013
Max 1hr Temp Fall 1.6 °C 01:44 1.7 °C 3.4 °C, 2023 1.2 °C, 2017
Max 1hr Hum Fall 13% 03:34 11% 24%, 2016 8%, 2020
Max 10m Wind Speed 7.3 mph 02:11 8.2 mph 14.4 mph, 2024 5.9 mph, 2019
Minimum Feels-like 16.1 °C 10:14 15.0 °C 23.4 °C, 2022 8.0 °C, 2014
Maximum Feels-like 19.4 °C 14:51 24.4 °C 32.5 °C, 2023 18.9 °C, 2014
Mean Feels-like 17.8 °C 19.8 °C 27.6 °C, 2022 14.2 °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 2.7 °C (-5.6) 8.5 °C (-0.0) 16.2 °C (+7.9), 2016 2.7 °C (-5.6), 2011
Humidity Range 22% 36% 57%, 2016 22%, 2011
Pressure Range 7 hPa 5 hPa 11 hPa, 2009 3 hPa, 2017
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]112 hrs (80%) [36%] 12.9 [100%], 2016 0 [0%], 2011
Wet Hours 5
[Mean rain rate: 2.0 mm/h]		26 hrs (91%) [4.7%] 7, 2010 0, 2009
Cloud Cover Overcast
Events None
Comments 08-11 Moderate/Heavy Rain, -20 broken Light Drizzle
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 23rd August 2011.
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