Daily Report for 15th May 2012

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 4.8 °C (-4.2) 23:58 7.4 °C (-0.8) 13.0 °C (+4.0), 2024 2.3 °C (-6.7), 2020
Maximum Temperature 11.5 °C (-6.2) 14:48 13.6 °C (-3.5) 22.6 °C (+4.9), 2018 11.5 °C (-6.2), 2012
Mean Temperature 7.5 °C (-5.2) 10.6 °C (-2.1) 17.1 °C, 2024 7.5 °C, 2012
Minimum Humidity 56% 13:14 60% 72%, 2022 38%, 2014
Maximum Humidity 91% 09:04 90% 97%, 2015 73%, 2018
Mean Humidity 79% 77% 83%, 2021 58%, 2010
Minimum Pressure 1011 hPa 05:48 1012 hPa 1033 hPa, 2014 987 hPa, 2013
Maximum Pressure 1023 hPa 22:57 1020 hPa 1036 hPa, 2014 1001 hPa, 2013
Mean Pressure 1017 hPa 1016 hPa 1035 hPa, 2014 994 hPa, 2013
Mean Wind Speed 4.7 mph (+0.0) 5.0 mph (+0.3) 8.7 mph, 2009 0.8 mph, 2021
Maximum Wind Speed 17.5 mph 13.1 mph 21.5 mph, 2013 6.7 mph, 2014
Maximum Gust 25.1 mph 13:13 18.9 mph 31.0 mph, 2009 8.7 mph, 2014
Mean Wind Direction NW
Rainfall 5.9 mm 44.2 mm (199%) 5.9 mm, 2012
Maximum Hourly Rain 1.8 mm 08:07 2.9 mm, 2021
Maximum 10-min Rain 0.8 mm 18:02 1.7 mm, 2021
Maximum Rain Rate 8 mm/h 18:03 16 mm/h, 2009
Minimum Dew Point 2.2 °C 15:26 3.9 °C 9.5 °C, 2022 0.2 °C, 2020
Maximum Dew Point 6.2 °C 17:49 9.1 °C 14.3 °C, 2022 6.2 °C, 2012
Mean Dew Point 3.9 °C 6.4 °C 12.1 °C, 2022 3.3 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 5.0 °C * 08:10 7.8 °C 13.5 °C, 2024 2.3 °C, 2020
Day Maximum (09-21) 11.5 °C 14:48 13.6 °C 22.6 °C, 2018 11.5 °C, 2012
Max 10m Temp Rise 0.8 °C 16:09 0.6 °C 1.2 °C, 2024 0.4 °C, 2022
Max 1hr Temp Rise 2.0 °C 11:48 1.9 °C 4.7 °C, 2020 1.2 °C, 2009
Max 1hr Hum Rise 15% 17:13 8% 21%, 2024 5%, 2011
Max 10m Temp Fall 1.6 °C 16:26 0.5 °C 1.6 °C, 2012 0.4 °C, 2010
Max 1hr Temp Fall 3.3 °C 17:13 1.6 °C 3.3 °C, 2012 1.0 °C, 2015
Max 1hr Hum Fall 14% 11:58 10% 22%, 2020 6%, 2022
Max 10m Wind Speed 8.9 mph 18:03 8.3 mph 16.4 mph, 2013 4.8 mph, 2014
Minimum Feels-like 1.1 °C 08:45 6.0 °C 14.8 °C, 2024 1.1 °C, 2012
Maximum Feels-like 11.5 °C 14:48 14.5 °C 25.5 °C, 2018 11.5 °C, 2012
Mean Feels-like 6.2 °C 10.6 °C 19.3 °C, 2024 6.2 °C, 2012
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 6.7 °C (-2.0) 6.2 °C (-2.7) 16.5 °C (+7.8), 2020 5.1 °C (-3.7), 2022
Humidity Range 35% 31% 49%, 2014 17%, 2022
Pressure Range 12 hPa 8 hPa 14 hPa, 2013 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 3.5 [25%]41 hrs (46%) [20%] 14 [99%], 2018 0 [0%], 2017
Wet Hours 4
[Mean rain rate: 1.5 mm/h]		37 hrs (189%) [10%] 4, 2009 0, 2010
Cloud Cover Mostly Cloudy
Events Thunder
Comments 07-0830 Light-Moderate Rain; 13--20 Light-Moderate Showers with Thunder
Extra Comments Thundery around and about, with Hail reported in Finchley
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 15th May 2012.
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

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Webcam Summary of Cloud Conditions

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Wind rose