Daily Report for 30th May 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 9.3 °C (-1.5) 05:24 8.9 °C (-0.2) 15.0 °C (+4.2), 2017 5.2 °C (-5.6), 2022
Maximum Temperature 23.1 °C (+3.8) 14:36 18.4 °C (+0.6) 25.4 °C (+6.1), 2012 15.1 °C (-4.2), 2013
Mean Temperature 16.1 °C (+1.2) 13.4 °C (+0.2) 19.2 °C, 2012 10.7 °C, 2022
Minimum Humidity 30% 15:32 46% 80%, 2018 30%, 2009
Maximum Humidity 90% 07:20 87% 97%, 2013 81%, 2015
Mean Humidity 59% 68% 90%, 2018 55%, 2015
Minimum Pressure 1025 hPa 17:27 1015 hPa 1030 hPa, 2023 1006 hPa, 2010
Maximum Pressure 1028 hPa 01:55 1021 hPa 1032 hPa, 2023 1013 hPa, 2011
Mean Pressure 1026 hPa 1018 hPa 1031 hPa, 2023 1010 hPa, 2011
Mean Wind Speed 4.6 mph (-0.1) 5.8 mph (+1.1) 8.1 mph, 2019 1.6 mph, 2018
Maximum Wind Speed n/a 0.0 mph 19.1, 2019 7, 2018
Maximum Gust 23.0 mph 24.0 mph 27.6 mph, 2019 12.7 mph, 2018
Mean Wind Direction n/a
Rainfall 0.0 mm 26.3 mm (59%) 5.1 mm, 2013
Maximum Hourly Rain n/a 2, 2013
Maximum 10-min Rain n/a 0.6, 2013
Maximum Rain Rate n/a 2.8, 2013
Minimum Dew Point 4.5 °C 18:24 4.0 °C 11.7 °C, 2018 1.2 °C, 2015
Maximum Dew Point 11.9 °C 09:15 10.3 °C 17.0 °C, 2018 6.3 °C, 2015
Mean Dew Point 7.2 °C 7.1 °C 13.9 °C, 2018 3.3 °C, 2015
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 9.3 °C 9.0 °C 15.0 °C, 2017 5.2 °C, 2022
Day Maximum (09-21) 23.1 °C 18.4 °C 25.4 °C, 2012 15.1 °C, 2013
Max 10m Temp Rise 0.9 °C 09:57 0.7 °C 0.9 °C, 2009 0.4 °C, 2014
Max 1hr Temp Rise 3.4 °C 10:18 2.3 °C 3.5 °C, 2022 1.2 °C, 2016
Max 1hr Hum Rise 8% 20:11 8% 22%, 2012 4%, 2013
Max 10m Temp Fall 0.5 °C 19:12 0.5 °C 1.0 °C, 2012 0.2 °C, 2016
Max 1hr Temp Fall 2.2 °C 19:19 1.6 °C 3.2 °C, 2012 0.9 °C, 2016
Max 1hr Hum Fall 18% 10:09 13% 20%, 2012 6%, 2023
Max 10m Wind Speed n/a 0.0 mph 12.6, 2019 4.9, 2018
Minimum Feels-like n/a 0.0 °C 17.2, 2017 2.2, 2022
Maximum Feels-like n/a 0.0 °C 27.5, 2019 15.8, 2022
Mean Feels-like n/a 0.0 °C 22.1, 2019 10.9, 2022
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 13.8 °C (+5.3) 9.6 °C (+0.8) 14.3 °C (+5.8), 2020 4.4 °C (-4.1), 2013
Humidity Range 60% 41% 60%, 2009 15%, 2018
Pressure Range 3 hPa 5 hPa 10 hPa, 2010 1 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 13.8 [94%]182 hrs (100%) [43%] 14.8 [100%], 2020 0 [0%], 2014
Wet Hours 028 hrs (71%) [3.8%] 5, 2013 0, 2009
Cloud Cover not available
Events None
Comments -
Extra Comments
Issues Tmax corrected as unreliable
Observer Absent? No
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 30th May 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