Daily Report for 22nd December 2009

<<Previous Day
Reset
Next Day>>
Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature -2.3 °C (-5.7) 23:58 1.8 °C (-1.9) 11.6 °C (+8.2), 2014 -2.3 °C (-5.7), 2009
Maximum Temperature 1.3 °C (-6.4) 15:07 6.2 °C (-2.1) 14.9 °C (+7.2), 2015 1.3 °C (-6.4), 2009
Mean Temperature 0.0 °C (-6.1) 4.1 °C (-2.0) 13.5 °C, 2015 0.0 °C, 2009
Minimum Humidity 96% 16:35 82% 96%, 2009 59%, 2013
Maximum Humidity 98% 12:00 97% 98%, 2009 83%, 2016
Mean Humidity 98% 91% 98%, 2009 74%, 2013
Minimum Pressure 983 hPa 03:21 1005 hPa 1034 hPa, 2017 974 hPa, 2019
Maximum Pressure 990 hPa 23:14 1013 hPa 1037 hPa, 2017 990 hPa, 2009
Mean Pressure 986 hPa 1009 hPa 1036 hPa, 2017 986 hPa, 2019
Mean Wind Speed 2.9 mph (-2.2) 4.5 mph (-0.6) 11.9 mph, 2015 1.7 mph, 2021
Maximum Wind Speed 9.2 mph 11.0 mph 23.5 mph, 2015 7.2 mph, 2021
Maximum Gust 14.8 mph 10:14 16.3 mph 43.4 mph, 2015 11.4 mph, 2021
Mean Wind Direction W
Rainfall 0.0 mm 50.0 mm (124%) 17.8 mm, 2012
Maximum Hourly Rain n/a 01:20 4.5, 2015
Maximum 10-min Rain n/a 01:20 2.7, 2015
Maximum Rain Rate n/a 126, 2015
Minimum Dew Point -2.6 °C 23:58 0.2 °C 9.0 °C, 2015 -2.8 °C, 2021
Maximum Dew Point 1.0 °C 14:58 5.4 °C 12.6 °C, 2012 0.9 °C, 2010
Mean Dew Point -0.3 °C 2.7 °C 11.1 °C, 2015 -0.3 °C, 2009
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * -0.3 °C * 2.6 °C 11.2 °C, 2014 -1.4 °C, 2021
Day Maximum (09-21) 1.3 °C 6.0 °C 14.9 °C, 2015 1.3 °C, 2009
Max 10m Temp Rise 0.3 °C 14:34 0.4 °C 0.5 °C, 2021 0.1 °C, 2010
Max 1hr Temp Rise 0.5 °C 13:56 1.0 °C 1.9 °C, 2021 0.2 °C, 2010
Max 1hr Hum Rise 1% 17:26 4% 9%, 2023 1%, 2009
Max 10m Temp Fall 0.3 °C 20:53 0.4 °C 0.7 °C, 2013 0.1 °C, 2012
Max 1hr Temp Fall 0.9 °C 21:15 0.9 °C 1.9 °C, 2016 0.3 °C, 2012
Max 1hr Hum Fall 2% 15:54 6% 12%, 2013 1%, 2012
Max 10m Wind Speed 7.6 mph 12:17 7.8 mph 18.1 mph, 2015 5.4 mph, 2021
Minimum Feels-like -5.1 °C 10:14 -1.5 °C 11.9 °C, 2015 -5.3 °C, 2010
Maximum Feels-like 1.3 °C 14:59 6.7 °C 16.8 °C, 2015 1.1 °C, 2010
Mean Feels-like -1.0 °C 3.0 °C 15.3 °C, 2015 -1.3 °C, 2010
Air-frost Hrs 8 hrs 4 hrs 10 hrs, 2021 0 hrs, 2011
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.6 °C (-0.7) 4.4 °C (-0.2) 6.3 °C (+2.0), 2012 1.5 °C (-2.8), 2010
Humidity Range 2% 15% 25%, 2013 2%, 2009
Pressure Range 7 hPa 8 hPa 24 hPa, 2019 3 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 3 [43%]62 hrs (135%) [40%] 6.5 [93%], 2011 0 [0%], 2010
Wet Hours 059 hrs (133%) [11%] 16, 2012 0, 2009
Cloud Cover not available
Events Lying Snow (at 09z): ~6 cm
Air Frost
Comments Lying Snow: 6cm
Extra Comments 22nd-25th: RHeavy at 98% from 20z on 22nd to 12z on 25th (64 hrs)
Issues None known
Observer Absent? No
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 22nd December 2009.
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

daygraph daygraph 2 daygraph-wdir

Webcam Summary of Cloud Conditions


Webcam summary not available for this day

Wind rose