Daily Report for 1st May 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 7.9 °C (+0.8) 06:22 7.9 °C (+0.7) 11.2 °C (+4.1), 2024 1.5 °C (-5.6), 2016
Maximum Temperature 21.0 °C (+4.9) 14:54 21.0 °C (+4.8) 21.0 °C (+4.9), 2009 12.3 °C (-3.8), 2021
Mean Temperature 14.1 °C (+2.9) 14.1 °C (+2.7) 15.2 °C, 2024 7.6 °C, 2021
Minimum Humidity 40% 19:29 40% 72%, 2014 33%, 2016
Maximum Humidity 94% 08:15 94% 97%, 2012 66%, 2011
Mean Humidity 68% 68% 90%, 2014 52%, 2011
Minimum Pressure 1021 hPa 01:42 1021 hPa 1026 hPa, 2016 997 hPa, 2020
Maximum Pressure 1025 hPa 22:25 1025 hPa 1029 hPa, 2016 1006 hPa, 2020
Mean Pressure 1023 hPa 1023 hPa 1027 hPa, 2016 1000 hPa, 2020
Mean Wind Speed 3.9 mph (-0.8) 3.9 mph (-0.8) 9.2 mph, 2011 1.6 mph, 2014
Maximum Wind Speed n/a 0.0 mph 18.5, 2011 8.5, 2014
Maximum Gust 16.0 mph 16.0 mph 27.3 mph, 2011 12.3 mph, 2014
Mean Wind Direction n/a
Rainfall 0.0 mm 0.0 mm (0%) 31.7 mm, 2010
Maximum Hourly Rain n/a 13.1, 2010
Maximum 10-min Rain n/a 4.1, 2010
Maximum Rain Rate n/a 60, 2010
Minimum Dew Point 2.9 °C 19:30 2.9 °C 10.3 °C, 2024 -2.7 °C, 2013
Maximum Dew Point 11.0 °C 10:54 11.0 °C 14.6 °C, 2024 2.8 °C, 2015
Mean Dew Point 7.8 °C 7.8 °C 12.3 °C, 2024 0.8 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 7.9 °C 7.9 °C 11.2 °C, 2024 1.5 °C, 2016
Day Maximum (09-21) 21.0 °C 21.0 °C 21.0 °C, 2009 12.3 °C, 2021
Max 10m Temp Rise 1.6 °C 09:17 1.6 °C 1.6 °C, 2009 0.3 °C, 2014
Max 1hr Temp Rise 3.5 °C 10:09 3.5 °C 4.5 °C, 2016 0.7 °C, 2014
Max 1hr Hum Rise 13% 20:55 13% 18%, 2020 4%, 2014
Max 10m Temp Fall 0.9 °C 09:09 0.9 °C 2.4 °C, 2020 0.3 °C, 2014
Max 1hr Temp Fall 1.6 °C 18:16 1.6 °C 3.3 °C, 2020 0.7 °C, 2014
Max 1hr Hum Fall 15% 10:07 15% 22%, 2013 3%, 2014
Max 10m Wind Speed n/a 0.0 mph 13, 2018 6.2, 2014
Minimum Feels-like n/a 0.0 °C 12.6, 2024 -0.9, 2018
Maximum Feels-like n/a 0.0 °C 23.1, 2024 12.3, 2021
Mean Feels-like n/a 0.0 °C 17.7, 2024 7.1, 2021
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 13.1 °C (+4.1) 13.1 °C (+4.1) 15.3 °C (+6.3), 2016 3.2 °C (-5.8), 2014
Humidity Range 54% 54% 56%, 2013 17%, 2017
Pressure Range 4 hPa 4 hPa 16 hPa, 2017 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 10.2 [76%]10 hrs (177%) [76%] 11 [82%], 2011 0 [0%], 2014
Wet Hours 00 hrs (0%) [0%] 13, 2014 0, 2009
Cloud Cover not available
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 1st 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