Daily Report for 27th December 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 2.6 °C (-0.8) 23:55 1.7 °C (-1.9) 12.4 °C (+9.0), 2015 0.2 °C (-3.2), 2016
Maximum Temperature 6.3 °C (-1.5) 12:03 6.1 °C (-2.1) 14.5 °C (+6.7), 2015 4.1 °C (-3.7), 2010
Mean Temperature 4.9 °C (-1.1) 4.0 °C (-2.0) 14.0 °C, 2015 2.3 °C, 2016
Minimum Humidity 68% 16:15 83% 92%, 2021 66%, 2010
Maximum Humidity 95% 00:02 97% 98%, 2013 80%, 2010
Mean Humidity 81% 91% 94%, 2021 71%, 2011
Minimum Pressure 996 hPa 07:29 1003 hPa 1041 hPa, 2016 973 hPa, 2020
Maximum Pressure 1006 hPa 23:21 1010 hPa 1046 hPa, 2016 991 hPa, 2013
Mean Pressure 1001 hPa 1006 hPa 1044 hPa, 2016 978 hPa, 2020
Mean Wind Speed 7.4 mph (+2.3) 4.5 mph (-0.6) 10.5 mph, 2013 0.3 mph, 2018
Maximum Wind Speed 16.3 mph 10.9 mph 27.8 mph, 2020 4.1 mph, 2018
Maximum Gust 25.5 mph 14:18 16.6 mph 41.1 mph, 2020 5.8 mph, 2018
Mean Wind Direction W
Rainfall 0.0 mm 58.6 mm (118%) 11.4 mm, 2020
Maximum Hourly Rain n/a 2.7, 2013
Maximum 10-min Rain n/a 1.3, 2013
Maximum Rain Rate n/a 18, 2013
Minimum Dew Point -0.7 °C 23:21 0.2 °C 9.6 °C, 2015 -3.1 °C, 2016
Maximum Dew Point 4.7 °C 00:02 5.3 °C 12.6 °C, 2015 0.7 °C, 2010
Mean Dew Point 1.9 °C 2.6 °C 11.4 °C, 2015 -1.5 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 4.2 °C * 2.5 °C 13.4 °C, 2015 -0.4 °C, 2010
Day Maximum (09-21) 6.3 °C 6.0 °C 14.5 °C, 2015 2.9 °C, 2017
Max 10m Temp Rise 0.3 °C 10:00 0.4 °C 0.5 °C, 2022 0.1 °C, 2011
Max 1hr Temp Rise 0.8 °C 10:30 1.0 °C 1.8 °C, 2022 0.3 °C, 2011
Max 1hr Hum Rise 4% 19:26 4% 10%, 2013 1%, 2021
Max 10m Temp Fall 0.3 °C 22:31 0.4 °C 1.2 °C, 2014 0.2 °C, 2010
Max 1hr Temp Fall 1.0 °C 16:50 0.9 °C 4.9 °C, 2014 0.5 °C, 2021
Max 1hr Hum Fall 7% 12:24 5% 13%, 2013 1%, 2015
Max 10m Wind Speed 10.1 mph 12:35 7.8 mph 22.5 mph, 2020 3.3 mph, 2018
Minimum Feels-like -1.1 °C 22:59 -1.5 °C 13.9 °C, 2015 -6.3 °C, 2017
Maximum Feels-like 5.1 °C 02:07 6.4 °C 17.0 °C, 2015 4.0 °C, 2010
Mean Feels-like 1.8 °C 2.7 °C 16.0 °C, 2015 -1.4 °C, 2017
Air-frost Hrs 0 hrs 3 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.7 °C (-0.7) 4.4 °C (-0.2) 9.2 °C (+4.8), 2020 1.6 °C (-2.8), 2010
Humidity Range 27% 14% 32%, 2013 4%, 2021
Pressure Range 10 hPa 8 hPa 23 hPa, 2012 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 2 [29%]70 hrs (123%) [36%] 5 [71%], 2016 0 [0%], 2010
Wet Hours 069 hrs (128%) [11%] 8, 2017 0, 2009
Cloud Cover not available
Events None
Comments -
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 27th 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.
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Daily Graph of Conditions

daygraph daygraph 2 daygraph-wdir

Webcam Summary of Cloud Conditions


Webcam summary not available for this day

Wind rose