Daily Report for 11th December 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 3.0 °C (-0.7) 01:29 3.5 °C (-0.4) 6.7 °C (+3.0), 2020 -3.9 °C (-7.6), 2022
Maximum Temperature 8.6 °C (+0.2) 14:40 8.8 °C (+0.0) 10.8 °C (+2.4), 2020 -0.1 °C (-8.5), 2022
Mean Temperature 6.6 °C (-0.2) 6.5 °C (-0.2) 9.1 °C, 2015 -1.9 °C, 2022
Minimum Humidity 75% 15:05 65% 96%, 2009 65%, 2014
Maximum Humidity 93% 23:59 88% 98%, 2009 79%, 2016
Mean Humidity 84% 78% 98%, 2009 77%, 2014
Minimum Pressure 1001 hPa 21:35 1003 hPa 1032 hPa, 2024 978 hPa, 2017
Maximum Pressure 1016 hPa 00:18 1012 hPa 1034 hPa, 2009 993 hPa, 2020
Mean Pressure 1008 hPa 1008 hPa 1033 hPa, 2024 985 hPa, 2017
Mean Wind Speed 5.7 mph (+0.6) 6.1 mph (+1.0) 8.7 mph, 2014 0.6 mph, 2013
Maximum Wind Speed 15.9 mph 15.9 mph 18.7 mph, 2023 4.0 mph, 2013
Maximum Gust 22.5 mph 17:11 23.2 mph 32.3 mph, 2023 5.9 mph, 2013
Mean Wind Direction SSW
Rainfall 5.6 mm 13.9 mm (69%) 16.1 mm, 2017
Maximum Hourly Rain 5.3 mm 20:20 5.3 mm, 2011
Maximum 10-min Rain 2.0 mm 20:02 2.0 mm, 2011
Maximum Rain Rate 20 mm/h 19:58 24 mm/h, 2015
Minimum Dew Point 0.3 °C 01:28 -0.1 °C 5.7 °C, 2020 -4.6 °C, 2022
Maximum Dew Point 7.0 °C 20:07 5.7 °C 9.9 °C, 2021 -0.5 °C, 2022
Mean Dew Point 4.2 °C 2.8 °C 7.9 °C, 2020 -2.4 °C, 2022
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 3.0 °C 01:29 4.3 °C 9.5 °C, 2015 -3.9 °C, 2022
Day Maximum (09-21) 8.6 °C 14:39 8.6 °C 10.8 °C, 2020 -0.1 °C, 2022
Max 10m Temp Rise 0.3 °C 06:30 0.4 °C 0.6 °C, 2009 0.1 °C, 2015
Max 1hr Temp Rise 0.9 °C 10:19 1.2 °C 2.1 °C, 2018 0.4 °C, 2015
Max 1hr Hum Rise 5% 16:39 5% 9%, 2014 1%, 2009
Max 10m Temp Fall 0.3 °C 20:13 0.2 °C 0.6 °C, 2014 0.1 °C, 2021
Max 1hr Temp Fall 1.4 °C 21:00 0.8 °C 1.7 °C, 2012 0.4 °C, 2021
Max 1hr Hum Fall 4% 14:07 4% 12%, 2014 0%, 2013
Max 10m Wind Speed 11.2 mph 14:03 10.3 mph 14.9 mph, 2023 3.0 mph, 2013
Minimum Feels-like 1.2 °C 00:39 0.3 °C 4.1 °C, 2020 -6.8 °C, 2017
Maximum Feels-like 8.0 °C 20:23 8.4 °C 11.9 °C, 2021 -0.9 °C, 2017
Mean Feels-like 4.8 °C 4.7 °C 8.4 °C, 2023 -3.5 °C, 2017
Air-frost Hrs 0 hrs 0 hrs 24 hrs, 2022 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.6 °C (+1.0) 5.3 °C (+0.4) 8.5 °C (+3.9), 2021 1.4 °C (-3.2), 2024
Humidity Range 18% 23% 21%, 2014 2%, 2009
Pressure Range 15 hPa 9 hPa 20 hPa, 2017 2 hPa, 2024
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]32 hrs (135%) [40%] 7 [99%], 2012 0 [0%], 2011
Wet Hours 2
[Mean rain rate: 2.8 mm/h]		13 hrs (60%) [5%] 13, 2017 0, 2009
Cloud Cover Overcast
Events None
Comments 07, 10 Light Showers; 19-21 Moderate-Heavy Rain
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 11th December 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

day graph

Webcam Summary of Cloud Conditions

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Wind rose