Daily Report for 12th September 2016

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 10.0 °C (-1.8) 05:07 14.5 °C (+2.3) 14.6 °C (+2.8), 2011 6.2 °C (-5.6), 2024
Maximum Temperature 24.4 °C (+5.0) 15:35 22.1 °C (+1.9) 25.8 °C (+6.4), 2022 14.5 °C (-4.9), 2024
Mean Temperature 17.0 °C (+1.6) 18.3 °C (+2.1) 20.3 °C, 2022 10.0 °C, 2024
Minimum Humidity 56% 16:34 62% 72%, 2013 48%, 2011
Maximum Humidity 90% 08:20 89% 97%, 2013 83%, 2012
Mean Humidity 74% 78% 87%, 2018 65%, 2015
Minimum Pressure 1012 hPa 11:19 1013 hPa 1028 hPa, 2009 995 hPa, 2017
Maximum Pressure 1014 hPa 11:42 1020 hPa 1034 hPa, 2009 1007 hPa, 2017
Mean Pressure 1013 hPa 1016 hPa 1031 hPa, 2009 1004 hPa, 2017
Mean Wind Speed 3.6 mph (-0.3) 5.7 mph (+1.8) 10.8 mph, 2011 0.8 mph, 2021
Maximum Wind Speed 15.8 mph 13:50 16.3 mph 22.1 mph, 2011 5.6 mph, 2021
Maximum Gust 22.6 mph 13:23 23.9 mph 37.4 mph, 2011 8.7 mph, 2013
Mean Wind Direction SSW
Rainfall 0.0 mm 13.4 mm (67%) 3.1 mm, 2018
Maximum Hourly Rain n/a 2.3, 2012
Maximum 10-min Rain n/a 2.3, 2012
Maximum Rain Rate n/a 60, 2012
Minimum Dew Point 8.0 °C 04:10 11.5 °C 13.1 °C, 2022 2.6 °C, 2012
Maximum Dew Point 16.0 °C 12:26 16.8 °C 18.2 °C, 2022 10.0 °C, 2024
Mean Dew Point 13.2 °C 14.4 °C 16.3 °C, 2023 6.5 °C, 2024
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 10.0 °C 05:07 15.0 °C 17.7 °C, 2023 6.2 °C, 2024
Day Maximum (09-21) 24.4 °C 15:35 22.1 °C 25.8 °C, 2022 14.5 °C, 2024
Max 10m Temp Rise 0.8 °C 08:59 0.6 °C 0.9 °C, 2022 0.3 °C, 2018
Max 1hr Temp Rise 2.7 °C 08:56 1.9 °C 3.4 °C, 2012 1.1 °C, 2018
Max 1hr Hum Rise 9% 12:26 8% 19%, 2025 5%, 2011
Max 10m Temp Fall 0.5 °C 00:20 0.5 °C 1.3 °C, 2025 0.4 °C, 2010
Max 1hr Temp Fall 2.0 °C 01:08 1.6 °C 3.8 °C, 2025 1.0 °C, 2013
Max 1hr Hum Fall 10% 11:54 12% 16%, 2014 6%, 2013
Max 10m Wind Speed 12.5 mph 13:53 12.4 mph 14.8 mph, 2011 3.7 mph, 2021
Minimum Feels-like 7.7 °C 04:47 16.8 °C 17.5 °C, 2022 3.3 °C, 2024
Maximum Feels-like 28.9 °C 15:06 26.5 °C 31.8 °C, 2022 15.6 °C, 2024
Mean Feels-like 20.6 °C 22.1 °C 25.0 °C, 2022 9.2 °C, 2024
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 14.4 °C (+6.8) 7.6 °C (-0.4) 14.4 °C (+6.8), 2016 5.7 °C (-1.9), 2013
Humidity Range 34% 27% 44%, 2011 23%, 2018
Pressure Range 2 hPa 7 hPa 12 hPa, 2017 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 3.3 [28%]47 hrs (76%) [33%] 10 [86%], 2009 0.1 [1%], 2018
Wet Hours 021 hrs (128%) [7.3%] 6, 2018 0, 2009
Cloud Cover Partly Cloudy
Events None
Comments -
Extra Comments
Issues StAlbans T/H -13, then casa
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 12th September 2016.
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

day graph

Webcam Summary of Cloud Conditions

daycamsumLarge resolution version

Wind rose