Daily Report for 2nd September 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.3 °C (+0.5) 04:50 14.0 °C (+1.2) 16.6 °C (+3.8), 2023 8.1 °C (-4.7), 2019
Maximum Temperature 17.3 °C (-3.9) 15:47 19.0 °C (-2.1) 25.8 °C (+4.6), 2011 17.2 °C (-4.0), 2015
Mean Temperature 14.9 °C (-1.7) 15.9 °C (-0.5) 19.6 °C, 2022 13.2 °C, 2015
Minimum Humidity 69% 16:34 57% 72%, 2012 34%, 2018
Maximum Humidity 96% 23:07 90% 96%, 2009 80%, 2017
Mean Humidity 83% 74% 85%, 2023 59%, 2017
Minimum Pressure 995 hPa 23:32 999 hPa 1026 hPa, 2013 995 hPa, 2009
Maximum Pressure 1011 hPa 03:04 1010 hPa 1031 hPa, 2021 1011 hPa, 2009
Mean Pressure 1003 hPa 1005 hPa 1029 hPa, 2021 1003 hPa, 2009
Mean Wind Speed 5.2 mph (+1.3) 5.8 mph (+1.9) 6.6 mph, 2016 0.7 mph, 2017
Maximum Wind Speed 13.8 mph 15.6 mph 15.6 mph, 2016 7.3 mph, 2017
Maximum Gust 20.8 mph 13:46 28.2 mph 22.6 mph, 2016 10.5 mph, 2017
Mean Wind Direction S
Rainfall 9.3 mm 9.6 mm (288%) 9.3 mm, 2009
Maximum Hourly Rain 3.6 mm 21:02 3.6 mm, 2009
Maximum 10-min Rain 0.8 mm 20:26 1.6 mm, 2015
Maximum Rain Rate 16 mm/h 20:04 42 mm/h, 2015
Minimum Dew Point 10.0 °C 02:53 8.6 °C 15.0 °C, 2023 5.5 °C, 2019
Maximum Dew Point 14.3 °C 23:32 13.3 °C 17.7 °C, 2022 11.3 °C, 2017
Mean Dew Point 12.1 °C 11.1 °C 16.3 °C, 2023 8.0 °C, 2017
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.3 °C 14.0 °C 16.6 °C, 2023 8.1 °C, 2019
Day Maximum (09-21) 17.3 °C 19.0 °C 25.8 °C, 2011 17.2 °C, 2015
Max 10m Temp Rise 0.4 °C 13:30 0.2 °C 0.7 °C, 2010 0.4 °C, 2009
Max 1hr Temp Rise 1.2 °C 12:01 0.6 °C 3.5 °C, 2010 1.2 °C, 2009
Max 1hr Hum Rise 12% 17:26 6% 18%, 2020 4%, 2021
Max 10m Temp Fall 0.5 °C 02:05 0.2 °C 0.9 °C, 2017 0.3 °C, 2010
Max 1hr Temp Fall 1.5 °C 17:21 0.8 °C 2.5 °C, 2013 0.7 °C, 2012
Max 1hr Hum Fall 10% 12:51 5% 19%, 2014 5%, 2016
Max 10m Wind Speed 9.0 mph 16:40 10.3 mph 11.6 mph, 2016 5.3 mph, 2017
Minimum Feels-like 14.6 °C 04:50 15.4 °C 20.7 °C, 2023 6.2 °C, 2019
Maximum Feels-like 20.3 °C 15:31 22.0 °C 29.7 °C, 2022 19.3 °C, 2015
Mean Feels-like 17.3 °C 17.7 °C 24.1 °C, 2022 14.5 °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 4.0 °C (-4.4) 5.0 °C (-3.4) 13.2 °C (+4.8), 2019 4.0 °C (-4.4), 2009
Humidity Range 27% 33% 58%, 2018 18%, 2016
Pressure Range 16 hPa 12 hPa 16 hPa, 2009 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 1 [8%]8 hrs (76%) [33%] 12.3 [100%], 2018 0 [0%], 2016
Wet Hours 5
[Mean rain rate: 1.9 mm/h]
5.5 hrs (201%) [11%] 5, 2009 0, 2010
Cloud Cover not available
Events None
Comments 9-11 Light, 13-14 Light, 17 Heavy, 19-22 Moderate/Heavy Rain/Showers
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 2nd September 2009.
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

daygraph daygraph 2 daygraph-wdir

Webcam Summary of Cloud Conditions


Webcam summary not available for this day

Wind rose