Daily Report for 4th December 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 3.9 °C (-0.1) 23:46 5.1 °C (+1.1) 6.1 °C (+2.1), 2015 0.1 °C (-3.9), 2019
Maximum Temperature 9.3 °C (+0.2) 14:10 10.1 °C (+1.0) 12.8 °C (+3.8), 2015 5.2 °C (-3.9), 2020
Mean Temperature 7.5 °C (+0.1) 8.1 °C (+1.0) 10.0 °C, 2015 3.1 °C, 2019
Minimum Humidity 73% 12:31 68% 92%, 2023 51%, 2016
Maximum Humidity 85% 21:40 92% 97%, 2009 78%, 2016
Mean Humidity 79% 82% 94%, 2023 69%, 2016
Minimum Pressure 996 hPa 17:36 1002 hPa 1030 hPa, 2017 973 hPa, 2020
Maximum Pressure 1004 hPa 07:44 1008 hPa 1036 hPa, 2017 985 hPa, 2020
Mean Pressure 1000 hPa 1005 hPa 1033 hPa, 2017 978 hPa, 2020
Mean Wind Speed 5.3 mph (+0.2) 5.2 mph (+0.1) 8.3 mph, 2015 0.7 mph, 2019
Maximum Wind Speed 11.8 mph 16.2 mph 23.7 mph, 2015 5.1 mph, 2019
Maximum Gust 16.8 mph 12:03 23.3 mph 36.7 mph, 2015 8.0 mph, 2019
Mean Wind Direction WSW
Rainfall 0.3 mm 7.2 mm (98%) 3.8 mm, 2020
Maximum Hourly Rain n/a 20:37 1.9, 2021
Maximum 10-min Rain n/a 20:37 0.7, 2021
Maximum Rain Rate n/a 18, 2020
Minimum Dew Point 1.4 °C 23:46 2.3 °C 4.7 °C, 2023 -3.1 °C, 2016
Maximum Dew Point 6.1 °C 02:12 8.1 °C 10.9 °C, 2015 0.6 °C, 2016
Mean Dew Point 4.1 °C 5.0 °C 6.0 °C, 2015 -1.4 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 7.3 °C * 06:20 6.7 °C 7.3 °C, 2011 -1.4 °C, 2010
Day Maximum (09-21) 9.3 °C 14:09 9.6 °C 12.3 °C, 2015 3.7 °C, 2014
Max 10m Temp Rise 0.1 °C 02:09 0.2 °C 1.1 °C, 2009 0.1 °C, 2011
Max 1hr Temp Rise 0.6 °C 11:57 1.1 °C 3.2 °C, 2021 0.2 °C, 2014
Max 1hr Hum Rise 5% 15:28 6% 11%, 2009 1%, 2023
Max 10m Temp Fall 0.2 °C 19:07 0.2 °C 0.6 °C, 2013 0.2 °C, 2010
Max 1hr Temp Fall 0.5 °C 19:40 0.6 °C 2.5 °C, 2015 0.5 °C, 2010
Max 1hr Hum Fall 3% 03:49 4% 14%, 2012 1%, 2023
Max 10m Wind Speed 7.1 mph 12:16 10.0 mph 15.1 mph, 2015 3.6 mph, 2019
Minimum Feels-like 0.3 °C 23:15 2.2 °C 2.1 °C, 2015 -3.8 °C, 2010
Maximum Feels-like 9.0 °C 15:00 10.1 °C 14.5 °C, 2015 4.0 °C, 2022
Mean Feels-like 5.6 °C 7.1 °C 9.1 °C, 2015 0.7 °C, 2020
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.4 °C (+0.3) 5.0 °C (-0.1) 7.8 °C (+2.7), 2024 2.0 °C (-3.1), 2022
Humidity Range 12% 24% 28%, 2012 4%, 2023
Pressure Range 8 hPa 6 hPa 17 hPa, 2015 1 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.1 [1%]7.6 hrs (88%) [26%] 7.2 [100%], 2019 0 [0%], 2010
Wet Hours 0.59.5 hrs (119%) [9.9%] 6, 2020 0, 2012
Cloud Cover am: Overcast
pm: Overcast transitioned to Mostly Cloudy
Events None
Comments 14, 19 Light,Moderate 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 4th 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