Daily Report for 10th August 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 15.1 °C (+0.7) 05:21 14.4 °C (-0.0) 18.8 °C (+4.4), 2020 9.2 °C (-5.2), 2011
Maximum Temperature 20.8 °C (-2.1) 11:59 22.6 °C (-0.6) 33.7 °C (+10.8), 2020 19.1 °C (-3.8), 2010
Mean Temperature 17.7 °C (-0.7) 18.1 °C (-0.3) 25.9 °C, 2020 14.7 °C, 2018
Minimum Humidity 58% 12:11 57% 69%, 2010 36%, 2013
Maximum Humidity 92% 23:31 93% 96%, 2023 71%, 2013
Mean Humidity 74% 77% 86%, 2010 53%, 2013
Minimum Pressure 1014 hPa 17:41 1015 hPa 1024 hPa, 2022 992 hPa, 2014
Maximum Pressure 1018 hPa 01:44 1018 hPa 1030 hPa, 2022 1007 hPa, 2014
Mean Pressure 1016 hPa 1017 hPa 1027 hPa, 2022 999 hPa, 2014
Mean Wind Speed 4.3 mph (+0.3) 3.4 mph (-0.6) 12.3 mph, 2019 1.8 mph, 2012
Maximum Wind Speed 12.7 mph 8.3 mph 26.2 mph, 2019 6.9 mph, 2012
Maximum Gust 19.2 mph 15:01 13.9 mph 48.4 mph, 2019 9.7 mph, 2012
Mean Wind Direction SW
Rainfall 0.0 mm 36.4 mm (209%) 26.9 mm, 2014
Maximum Hourly Rain n/a 23.3, 2014
Maximum 10-min Rain n/a 8.9, 2014
Maximum Rain Rate n/a 119, 2018
Minimum Dew Point 9.7 °C 00:22 10.8 °C 16.2 °C, 2020 4.3 °C, 2016
Maximum Dew Point 16.4 °C 23:58 16.2 °C 20.7 °C, 2020 9.8 °C, 2013
Mean Dew Point 12.9 °C 13.6 °C 18.4 °C, 2020 6.9 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 15.1 °C 14.5 °C 18.8 °C, 2020 9.2 °C, 2011
Day Maximum (09-21) 20.8 °C 22.6 °C 33.7 °C, 2020 19.1 °C, 2010
Max 10m Temp Rise 0.6 °C 10:01 0.5 °C 0.9 °C, 2011 0.4 °C, 2010
Max 1hr Temp Rise 2.1 °C 10:17 1.7 °C 3.8 °C, 2011 1.4 °C, 2010
Max 1hr Hum Rise 8% 15:04 7% 20%, 2018 6%, 2015
Max 10m Temp Fall 0.7 °C 02:20 0.4 °C 1.7 °C, 2014 0.4 °C, 2015
Max 1hr Temp Fall 1.3 °C 03:11 1.4 °C 3.5 °C, 2014 1.0 °C, 2015
Max 1hr Hum Fall 10% 10:54 7% 22%, 2018 7%, 2010
Max 10m Wind Speed 8.1 mph 15:58 5.8 mph 18.0 mph, 2019 4.9 mph, 2012
Minimum Feels-like 16.4 °C 05:21 15.0 °C 23.5 °C, 2020 9.2 °C, 2011
Maximum Feels-like 23.4 °C 12:50 24.1 °C 40.7 °C, 2020 20.2 °C, 2016
Mean Feels-like 20.5 °C 19.4 °C 32.2 °C, 2020 15.5 °C, 2016
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.7 °C (-2.8) 8.1 °C (-0.5) 14.9 °C (+6.4), 2020 4.1 °C (-4.4), 2010
Humidity Range 34% 36% 53%, 2012 15%, 2015
Pressure Range 4 hPa 4 hPa 15 hPa, 2014 2 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [15%]44 hrs (71%) [32%] 13 [95%], 2022 0 [0%], 2010
Wet Hours 09.8 hrs (80%) [4.1%] 6, 2010 0, 2009
Cloud Cover not available
Events None
Comments -
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 10th August 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.
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Daily Graph of Conditions

daygraph daygraph 2 daygraph-wdir

Webcam Summary of Cloud Conditions


Webcam summary not available for this day

Wind rose