Daily Report for 30th December 2019

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 3.8 °C (+1.0) 05:33 4.2 °C (+1.0) 10.1 °C (+7.3), 2015 -1.4 °C (-4.2), 2014
Maximum Temperature 9.6 °C (+2.5) 14:43 9.3 °C (+1.4) 13.7 °C (+6.6), 2017 4.1 °C (-3.0), 2009
Mean Temperature 6.6 °C (+1.8) 6.9 °C (+1.2) 12.0 °C, 2015 1.3 °C, 2014
Minimum Humidity 85% 14:13 79% 98%, 2009 53%, 2015
Maximum Humidity 96% 08:22 94% 98%, 2009 81%, 2012
Mean Humidity 92% 87% 98%, 2009 72%, 2015
Minimum Pressure 1028 hPa 15:59 1002 hPa 1035 hPa, 2014 989 hPa, 2017
Maximum Pressure 1032 hPa 00:00 1015 hPa 1042 hPa, 2014 998 hPa, 2009
Mean Pressure 1030 hPa 1009 hPa 1038 hPa, 2014 994 hPa, 2009
Mean Wind Speed 5.4 mph (+0.3) 5.7 mph (+0.6) 11.5 mph, 2015 1.7 mph, 2016
Maximum Wind Speed 13.9 mph 12:08 14.8 mph 27.5 mph, 2013 5.6 mph, 2016
Maximum Gust 19.6 mph 07:12 24.2 mph 36.9 mph, 2013 7.3 mph, 2016
Mean Wind Direction WSW
Rainfall 0.0 mm 92.4 mm (174%) 6.3 mm, 2009
Maximum Hourly Rain n/a 3.1, 2015
Maximum 10-min Rain n/a 1.1, 2015
Maximum Rain Rate n/a 36, 2015
Minimum Dew Point 3.1 °C 05:33 2.4 °C 5.7 °C, 2018 -2.3 °C, 2014
Maximum Dew Point 7.2 °C 14:43 7.1 °C 10.0 °C, 2011 2.2 °C, 2020
Mean Dew Point 5.4 °C 4.9 °C 7.9 °C, 2017 -0.0 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 3.8 °C 05:31 4.9 °C 10.0 °C, 2015 -1.4 °C, 2014
Day Maximum (09-21) 9.6 °C 14:40 9.1 °C 13.7 °C, 2017 4.1 °C, 2009
Max 10m Temp Rise 0.4 °C 11:41 0.3 °C 0.5 °C, 2009 0.1 °C, 2010
Max 1hr Temp Rise 1.5 °C 12:07 1.1 °C 1.8 °C, 2017 0.3 °C, 2010
Max 1hr Hum Rise 3% 20:32 5% 10%, 2015 0%, 2009
Max 10m Temp Fall 0.3 °C 18:03 0.4 °C 0.5 °C, 2009 0.2 °C, 2010
Max 1hr Temp Fall 0.8 °C 20:03 1.3 °C 1.7 °C, 2020 0.3 °C, 2018
Max 1hr Hum Fall 7% 12:01 6% 13%, 2013 0%, 2009
Max 10m Wind Speed 11.3 mph 12:10 11.3 mph 18.6 mph, 2013 4.5 mph, 2016
Minimum Feels-like -0.8 °C 06:10 0.1 °C 10.2 °C, 2015 -5.6 °C, 2014
Maximum Feels-like 8.5 °C 15:14 9.0 °C 14.7 °C, 2017 4.1 °C, 2009
Mean Feels-like 4.1 °C 4.9 °C 12.3 °C, 2015 -1.0 °C, 2014
Air-frost Hrs 0 hrs 0 hrs 8 hrs, 2014 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.8 °C (+1.4) 5.1 °C (+0.4) 8.3 °C (+3.9), 2017 1.5 °C (-2.9), 2009
Humidity Range 11% 15% 36%, 2015 0%, 2009
Pressure Range 4 hPa 12 hPa 15 hPa, 2015 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 6 [85%]80 hrs (144%) [38%] 6 [85%], 2019 0 [0%], 2009
Wet Hours 0105 hrs (175%) [15%] 15, 2009 0, 2012
Cloud Cover am: Overcast transitioned to Sunny
pm: Sunny
Events Dense Fog
Comments fog til 9
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 5.5 °C
Notes
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 initially pulled from the official weather station at Heathrow, and later adjusted by hand to reflect local conditions based on webcam observations. Wet hrs are dervied algorithmically from rainfall data, though may be adjusted manually. Cloud cover and Events are manually reported, often with multi-week delays.
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Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

daycamsumFull resolution individual images at up-to 5 minute intervals

Wind rose