Daily Report for 29th December 2019

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 5.4 °C (+2.6) 23:48 4.2 °C (+1.0) 9.7 °C (+6.9), 2015 -2.3 °C (-5.1), 2017
Maximum Temperature 8.8 °C (+1.7) 14:50 9.3 °C (+1.4) 12.4 °C (+5.2), 2015 3.7 °C (-3.5), 2020
Mean Temperature 7.2 °C (+2.1) 6.9 °C (+1.2) 10.9 °C, 2015 1.1 °C, 2014
Minimum Humidity 82% 15:27 79% 98%, 2010 69%, 2011
Maximum Humidity 94% 23:00 94% 98%, 2009 83%, 2011
Mean Humidity 87% 87% 98%, 2010 73%, 2011
Minimum Pressure 1032 hPa 23:57 1002 hPa 1037 hPa, 2014 983 hPa, 2020
Maximum Pressure 1037 hPa 00:12 1014 hPa 1042 hPa, 2014 1000 hPa, 2020
Mean Pressure 1034 hPa 1008 hPa 1040 hPa, 2014 991 hPa, 2020
Mean Wind Speed 5.3 mph (+0.2) 5.7 mph (+0.6) 10.8 mph, 2012 0.3 mph, 2016
Maximum Wind Speed 11.2 mph 00:35 14.8 mph 18.4 mph, 2017 4.4 mph, 2016
Maximum Gust 16.0 mph 06:00 24.3 mph 28.8 mph, 2012 6.3 mph, 2016
Mean Wind Direction SSW
Rainfall 0.0 mm 92.4 mm (180%) 11.5 mm, 2009
Maximum Hourly Rain n/a 4.4, 2017
Maximum 10-min Rain n/a 1.9, 2011
Maximum Rain Rate n/a 72, 2015
Minimum Dew Point 4.2 °C 21:23 2.4 °C 6.6 °C, 2010 -3.3 °C, 2017
Maximum Dew Point 6.1 °C 14:53 7.1 °C 10.1 °C, 2018 1.1 °C, 2014
Mean Dew Point 5.1 °C 4.9 °C 8.0 °C, 2018 -1.1 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 7.2 °C * 06:27 4.9 °C 11.2 °C, 2012 -2.3 °C, 2017
Day Maximum (09-21) 8.8 °C 14:49 9.1 °C 12.3 °C, 2018 3.7 °C, 2020
Max 10m Temp Rise 0.2 °C 12:32 0.3 °C 0.6 °C, 2016 0.1 °C, 2010
Max 1hr Temp Rise 0.7 °C 13:51 1.1 °C 2.3 °C, 2017 0.4 °C, 2010
Max 1hr Hum Rise 3% 16:28 5% 8%, 2015 0%, 2010
Max 10m Temp Fall 0.2 °C 16:11 0.4 °C 0.5 °C, 2012 0.1 °C, 2009
Max 1hr Temp Fall 0.9 °C 16:58 1.3 °C 2.3 °C, 2016 0.3 °C, 2009
Max 1hr Hum Fall 2% 12:57 5% 10%, 2012 0%, 2010
Max 10m Wind Speed 8.4 mph 11:04 11.3 mph 14.6 mph, 2012 3.4 mph, 2016
Minimum Feels-like 1.8 °C 23:57 0.1 °C 6.5 °C, 2015 -5.1 °C, 2014
Maximum Feels-like 8.2 °C 14:52 9.0 °C 13.6 °C, 2018 3.1 °C, 2009
Mean Feels-like 4.8 °C 4.9 °C 11.1 °C, 2015 -1.0 °C, 2014
Air-frost Hrs 0 hrs 0 hrs 7 hrs, 2014 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.4 °C (-1.0) 5.1 °C (+0.4) 10.2 °C (+5.8), 2017 1.7 °C (-2.7), 2010
Humidity Range 12% 15% 24%, 2017 0%, 2010
Pressure Range 5 hPa 13 hPa 17 hPa, 2017 5 hPa, 2019
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 4 [57%]74 hrs (138%) [36%] 7 [100%], 2013 0 [0%], 2009
Wet Hours 0105 hrs (181%) [15%] 11, 2009 0, 2013
Cloud Cover Sunny with periods of Mostly Cloudy
Events None
Comments -
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

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Wind rose