Daily Report for 20th May 2015

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 5.1 °C (-4.4) 05:30 8.7 °C (+0.3) 14.1 °C (+4.6), 2014 5.1 °C (-4.4), 2015
Maximum Temperature 15.3 °C (-2.9) 18:35 16.7 °C (-0.6) 27.4 °C (+9.2), 2020 11.7 °C (-6.5), 2012
Mean Temperature 10.3 °C (-3.6) 12.5 °C (-0.1) 21.1 °C, 2020 10.1 °C, 2012
Minimum Humidity 44% 19:22 44% 80%, 2012 36%, 2020
Maximum Humidity 83% 05:59 86% 93%, 2013 67%, 2011
Mean Humidity 63% 65% 85%, 2013 53%, 2011
Minimum Pressure 1010 hPa 01:16 1008 hPa 1030 hPa, 2010 1002 hPa, 2021
Maximum Pressure 1023 hPa 22:55 1017 hPa 1033 hPa, 2010 1010 hPa, 2014
Mean Pressure 1016 hPa 1012 hPa 1032 hPa, 2010 1006 hPa, 2014
Mean Wind Speed 4.6 mph (-0.1) 6.6 mph (+1.9) 8.1 mph, 2021 1.5 mph, 2019
Maximum Wind Speed 12.5 mph 10:55 16.0 mph 22.2 mph, 2021 7.1 mph, 2010
Maximum Gust 17.5 mph 13:30 24.2 mph 35.4 mph, 2021 10.0 mph, 2010
Mean Wind Direction WNW
Rainfall 0.0 mm 44.2 mm (149%) 4.1 mm, 2022
Maximum Hourly Rain n/a 1.9, 2022
Maximum 10-min Rain n/a 0.8, 2017
Maximum Rain Rate n/a 18, 2017
Minimum Dew Point 1.1 °C 22:12 2.2 °C 8.3 °C, 2010 1.1 °C, 2015
Maximum Dew Point 5.7 °C 11:23 9.2 °C 14.9 °C, 2010 5.7 °C, 2015
Mean Dew Point 3.2 °C 5.7 °C 11.6 °C, 2010 3.2 °C, 2015
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 5.1 °C 05:30 8.9 °C 15.3 °C, 2014 5.1 °C, 2015
Day Maximum (09-21) 15.3 °C 18:35 16.7 °C 27.4 °C, 2020 11.7 °C, 2012
Max 10m Temp Rise 0.7 °C 11:48 0.6 °C 0.9 °C, 2009 0.4 °C, 2012
Max 1hr Temp Rise 2.6 °C 07:48 2.0 °C 3.6 °C, 2023 1.1 °C, 2012
Max 1hr Hum Rise 10% 15:20 9% 16%, 2021 2%, 2012
Max 10m Temp Fall 0.8 °C 15:11 0.6 °C 0.9 °C, 2017 0.2 °C, 2012
Max 1hr Temp Fall 2.5 °C 22:22 1.7 °C 2.8 °C, 2019 0.5 °C, 2012
Max 1hr Hum Fall 12% 12:20 14% 15%, 2018 5%, 2012
Max 10m Wind Speed 8.5 mph 10:43 12.3 mph 19.0 mph, 2021 4.9 mph, 2019
Minimum Feels-like 2.0 °C 05:04 6.5 °C 14.9 °C, 2016 2.0 °C, 2015
Maximum Feels-like 15.3 °C 18:32 17.0 °C 30.5 °C, 2020 12.4 °C, 2012
Mean Feels-like 9.5 °C 12.3 °C 23.1 °C, 2020 9.5 °C, 2015
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 10.2 °C (+1.5) 7.9 °C (-0.9) 15.1 °C (+6.4), 2020 3.1 °C (-5.6), 2012
Humidity Range 39% 41% 50%, 2020 7%, 2012
Pressure Range 13 hPa 9 hPa 20 hPa, 2021 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 7 [49%]111 hrs (92%) [40%] 14.4 [100%], 2018 0 [0%], 2012
Wet Hours 043 hrs (168%) [9%] 4, 2022 0, 2009
Cloud Cover am: Sunny transitioned to Mostly Cloudy
pm: Partly Cloudy
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? No
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 20th May 2015.
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

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Webcam Summary of Cloud Conditions

daycamsumLarge resolution version

Wind rose