Daily Report for 22nd December 2015

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 10.9 °C (+7.5) 23:48 9.5 °C (+5.8) 11.6 °C (+8.2), 2014 -2.3 °C (-5.7), 2009
Maximum Temperature 14.9 °C (+7.2) 10:56 13.3 °C (+5.0) 14.9 °C (+7.2), 2015 1.3 °C (-6.4), 2009
Mean Temperature 13.5 °C (+7.3) 11.6 °C (+5.4) 13.5 °C, 2015 0.0 °C, 2009
Minimum Humidity 74% 11:05 73% 96%, 2009 59%, 2013
Maximum Humidity 90% 03:30 89% 98%, 2009 83%, 2016
Mean Humidity 85% 82% 98%, 2009 74%, 2013
Minimum Pressure 1010 hPa 19:30 1015 hPa 1034 hPa, 2017 974 hPa, 2019
Maximum Pressure 1017 hPa 00:04 1022 hPa 1037 hPa, 2017 990 hPa, 2009
Mean Pressure 1012 hPa 1018 hPa 1036 hPa, 2017 986 hPa, 2019
Mean Wind Speed 11.9 mph (+6.8) 7.5 mph (+2.4) 11.9 mph, 2015 1.7 mph, 2021
Maximum Wind Speed 23.5 mph 10:24 17.4 mph 23.5 mph, 2015 7.2 mph, 2021
Maximum Gust 43.4 mph 10:24 26.0 mph 43.4 mph, 2015 11.4 mph, 2021
Mean Wind Direction SW
Rainfall 5.9 mm 37.5 mm (93%) 17.8 mm, 2012
Maximum Hourly Rain 4.5 mm 22:03 4.5 mm, 2015
Maximum 10-min Rain 2.7 mm 21:17 2.7 mm, 2015
Maximum Rain Rate 126 mm/h 21:17 126 mm/h, 2015
Minimum Dew Point 9.0 °C 00:00 6.2 °C 9.0 °C, 2015 -2.8 °C, 2021
Maximum Dew Point 12.6 °C 05:03 10.7 °C 12.6 °C, 2012 0.9 °C, 2010
Mean Dew Point 11.1 °C 8.5 °C 11.1 °C, 2015 -0.3 °C, 2009
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 9.9 °C * 21:26 10.1 °C 11.2 °C, 2014 -1.4 °C, 2021
Day Maximum (09-21) 14.9 °C 10:56 13.0 °C 14.9 °C, 2015 1.3 °C, 2009
Max 10m Temp Rise 0.3 °C 02:26 0.3 °C 0.5 °C, 2021 0.1 °C, 2010
Max 1hr Temp Rise 1.1 °C 03:15 1.0 °C 1.9 °C, 2021 0.2 °C, 2010
Max 1hr Hum Rise 4% 11:49 5% 13%, 2024 1%, 2009
Max 10m Temp Fall 0.7 °C 21:21 0.3 °C 0.7 °C, 2013 0.1 °C, 2012
Max 1hr Temp Fall 1.8 °C 21:56 1.0 °C 1.9 °C, 2016 0.3 °C, 2012
Max 1hr Hum Fall 9% 11:03 5% 12%, 2013 1%, 2012
Max 10m Wind Speed 18.1 mph 12:15 13.0 mph 18.1 mph, 2015 5.4 mph, 2021
Minimum Feels-like 11.9 °C 23:38 8.4 °C 11.9 °C, 2015 -5.3 °C, 2010
Maximum Feels-like 16.8 °C 05:12 14.7 °C 16.8 °C, 2015 1.1 °C, 2010
Mean Feels-like 15.3 °C 12.0 °C 15.3 °C, 2015 -1.3 °C, 2010
Air-frost Hrs 0 hrs 0 hrs 10 hrs, 2021 0 hrs, 2011
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 4.0 °C (-0.3) 3.8 °C (-0.8) 6.3 °C (+2.0), 2012 1.5 °C (-2.8), 2010
Humidity Range 16% 16% 25%, 2013 2%, 2009
Pressure Range 7 hPa 7 hPa 24 hPa, 2019 3 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.2 [3%]19 hrs (42%) [12%] 6.5 [93%], 2011 0 [0%], 2010
Wet Hours 5
[Mean rain rate: 1.2 mm/h]		55 hrs (126%) [10%] 16, 2012 0, 2009
Cloud Cover Overcast with periods of Mostly Cloudy
Events None
Comments Rain/Showers
Extra Comments
Issues None known
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 22nd December 2015.
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

daycamsumLarge resolution version

Wind rose