Daily Report for 7th September 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.8 °C (-0.5) 05:15 12.8 °C (+0.2) 18.5 °C (+6.2), 2016 8.8 °C (-3.5), 2018
Maximum Temperature 17.0 °C (-3.6) 15:35 20.3 °C (-0.6) 30.5 °C (+9.9), 2023 17.0 °C (-3.6), 2011
Mean Temperature 14.2 °C (-2.0) 16.4 °C (-0.2) 23.6 °C, 2023 13.5 °C, 2015
Minimum Humidity 63% 17:35 59% 78%, 2024 30%, 2012
Maximum Humidity 85% 23:59 89% 98%, 2024 83%, 2025
Mean Humidity 76% 75% 88%, 2024 57%, 2012
Minimum Pressure 1007 hPa 00:38 1008 hPa 1029 hPa, 2015 1000 hPa, 2010
Maximum Pressure 1012 hPa 09:38 1012 hPa 1032 hPa, 2015 1002 hPa, 2010
Mean Pressure 1010 hPa 1010 hPa 1031 hPa, 2015 1001 hPa, 2010
Mean Wind Speed 7.6 mph (+3.7) 6.3 mph (+2.4) 7.6 mph, 2011 0.3 mph, 2024
Maximum Wind Speed 16.1 mph 14.9 mph 17.3 mph, 2025 6.6 mph, 2024
Maximum Gust 23.7 mph 10:22 21.5 mph 26.5 mph, 2025 7.8 mph, 2014
Mean Wind Direction WSW
Rainfall 0.5 mm 26.3 mm (225%) 9.1 mm, 2022
Maximum Hourly Rain 0.5 mm 23:59 4.3 mm, 2022
Maximum 10-min Rain 0.3 mm 22:59 1.4 mm, 2022
Maximum Rain Rate n/a 30, 2022
Minimum Dew Point 9.0 °C 11:19 9.5 °C 16.3 °C, 2023 4.3 °C, 2012
Maximum Dew Point 11.1 °C 09:02 14.1 °C 20.1 °C, 2023 9.4 °C, 2018
Mean Dew Point 9.8 °C 11.8 °C 18.2 °C, 2023 6.9 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 11.8 °C 05:15 13.2 °C 18.5 °C, 2016 8.8 °C, 2018
Day Maximum (09-21) 17.0 °C 15:35 20.3 °C 30.5 °C, 2023 17.0 °C, 2011
Max 10m Temp Rise 0.5 °C 08:51 0.5 °C 0.9 °C, 2013 0.4 °C, 2014
Max 1hr Temp Rise 1.6 °C 09:19 1.8 °C 3.5 °C, 2021 1.1 °C, 2009
Max 1hr Hum Rise 6% 21:56 8% 15%, 2023 4%, 2009
Max 10m Temp Fall 0.4 °C 18:32 0.4 °C 1.1 °C, 2022 0.3 °C, 2017
Max 1hr Temp Fall 1.8 °C 18:51 1.5 °C 3.1 °C, 2012 0.8 °C, 2009
Max 1hr Hum Fall 9% 09:48 11% 15%, 2013 3%, 2009
Max 10m Wind Speed 11.3 mph 12:53 9.9 mph 14.1 mph, 2025 4.6 mph, 2014
Minimum Feels-like 12.6 °C 04:53 14.1 °C 24.1 °C, 2016 6.0 °C, 2018
Maximum Feels-like 18.5 °C 15:35 23.1 °C 37.7 °C, 2023 18.5 °C, 2011
Mean Feels-like 15.4 °C 18.7 °C 29.8 °C, 2023 13.6 °C, 2018
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 (-3.0) 7.5 °C (-0.8) 14.2 °C (+6.0), 2012 5.2 °C (-3.0), 2011
Humidity Range 22% 30% 57%, 2012 12%, 2009
Pressure Range 5 hPa 4 hPa 12 hPa, 2016 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 1.5 [13%]31 hrs (85%) [37%] 12 [100%], 2021 0 [0%], 2009
Wet Hours 1
[Mean rain rate: 0.5 mm/h]		10 hrs (105%) [6%] 5, 2022 0, 2009
Cloud Cover Overcast with periods of Mostly Cloudy
Events None
Comments 21-00 Light Rain/Drizzle Showers
Extra Comments
Issues None known
Observer Absent? No
Pond Temperature @ Hampstead Heath 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 7th September 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.
View monthly summary

Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

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Wind rose