Daily Report for 30th December 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 5.1 °C (+1.8) 18:23 4.1 °C (+0.5) 13.2 °C (+9.9), 2021 -1.4 °C (-4.7), 2014
Maximum Temperature 10.6 °C (+2.8) 23:53 9.0 °C (+0.8) 14.5 °C (+6.7), 2021 4.1 °C (-3.7), 2009
Mean Temperature 6.7 °C (+2.3) 6.7 °C (+0.7) 13.9 °C, 2021 1.3 °C, 2014
Minimum Humidity 91% 00:15 70% 98%, 2009 53%, 2015
Maximum Humidity 96% 23:59 90% 98%, 2009 81%, 2012
Mean Humidity 80% 81% 98%, 2009 72%, 2015
Minimum Pressure 1009 hPa 22:46 1007 hPa 1035 hPa, 2014 989 hPa, 2017
Maximum Pressure 1020 hPa 09:48 1016 hPa 1042 hPa, 2014 998 hPa, 2009
Mean Pressure 1014 hPa 1012 hPa 1038 hPa, 2014 994 hPa, 2009
Mean Wind Speed 5.2 mph (+0.1) 6.2 mph (+1.1) 11.5 mph, 2015 1.7 mph, 2016
Maximum Wind Speed 12.5 mph 15.5 mph 27.5 mph, 2013 5.6 mph, 2016
Maximum Gust 21.9 mph 00:14 23.0 mph 36.9 mph, 2013 7.3 mph, 2016
Mean Wind Direction WSW
Rainfall 4.8 mm 55.9 mm (101%) 6.3 mm, 2009
Maximum Hourly Rain 1.4 mm 16:39 3.1 mm, 2015
Maximum 10-min Rain 0.5 mm 16:23 1.1 mm, 2015
Maximum Rain Rate 24 mm/h 20:19 36 mm/h, 2015
Minimum Dew Point 5.4 °C 18:21 0.9 °C 11.1 °C, 2021 -2.3 °C, 2014
Maximum Dew Point 10.0 °C 23:53 6.4 °C 12.8 °C, 2021 2.2 °C, 2020
Mean Dew Point 3.5 °C 3.5 °C 12.0 °C, 2021 -0.0 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 5.1 °C 08:50 4.8 °C 12.4 °C, 2021 -1.4 °C, 2014
Day Maximum (09-21) * 7.3 °C * 14:00 8.5 °C 14.5 °C, 2021 4.1 °C, 2009
Max 10m Temp Rise n/a 18:30 0.3 °C 0.5, 2009 0.1, 2010
Max 1hr Temp Rise n/a 19:26 1.0 °C 1.9, 2022 0.3, 2010
Max 1hr Hum Rise n/a 19:43 5% 10, 2015 0, 2009
Max 10m Temp Fall 0.2 °C 18:19 0.3 °C 0.5 °C, 2009 0.2 °C, 2010
Max 1hr Temp Fall 0.6 °C 18:19 0.9 °C 1.7 °C, 2020 0.3 °C, 2018
Max 1hr Hum Fall 1% 18:38 4% 13%, 2013 0%, 2009
Max 10m Wind Speed 8.6 mph 00:24 9.1 mph 18.6 mph, 2013 4.5 mph, 2016
Minimum Feels-like -1.4 °C 18:19 0.3 °C 15.4 °C, 2021 -5.6 °C, 2014
Maximum Feels-like 11.7 °C 23:48 8.3 °C 17.1 °C, 2021 4.1 °C, 2009
Mean Feels-like 4.8 °C 4.7 °C 16.2 °C, 2021 -1.0 °C, 2014
Air-frost Hrs 0 hrs 0.2 hrs 8 hrs, 2014 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.5 °C (+1.0) 4.9 °C (+0.3) 8.3 °C (+3.8), 2017 1.3 °C (-3.2), 2021
Humidity Range 5% 19% 36%, 2015 0%, 2009
Pressure Range 11 hPa 10 hPa 21 hPa, 2023 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.1 [1%]68 hrs (108%) [32%] 6 [85%], 2019 0 [0%], 2009
Wet Hours 5
[Mean rain rate: 1.0 mm/h]
59 hrs (99%) [8.2%] 15, 2009 0, 2012
Cloud Cover am: Mostly Cloudy transitioned to Overcast
pm: Overcast
Events None
Comments 14-18 Light Rain, 20-22 Light 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 30th 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

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Webcam Summary of Cloud Conditions

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Wind rose