Daily Report for 31st March 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 8.3 °C (+3.0) 23:58 3.7 °C (-0.7) 11.2 °C (+5.9), 2017 -2.6 °C (-7.9), 2013
Maximum Temperature 13.4 °C (+0.7) 14:29 12.3 °C (+1.3) 21.1 °C (+8.4), 2021 5.6 °C (-7.1), 2013
Mean Temperature 10.8 °C (+1.9) 8.0 °C (+0.3) 14.4 °C, 2021 1.8 °C, 2013
Minimum Humidity 53% 16:39 52% 83%, 2023 37%, 2015
Maximum Humidity 73% 23:48 90% 97%, 2011 73%, 2009
Mean Humidity 63% 71% 92%, 2023 56%, 2015
Minimum Pressure 1022 hPa 18:03 1011 hPa 1030 hPa, 2020 981 hPa, 2010
Maximum Pressure 1025 hPa 06:54 1019 hPa 1034 hPa, 2020 998 hPa, 2023
Mean Pressure 1024 hPa 1015 hPa 1032 hPa, 2020 990 hPa, 2023
Mean Wind Speed 3.8 mph (-1.4) 5.0 mph (-0.2) 12.7 mph, 2015 1.0 mph, 2021
Maximum Wind Speed n/a 0.0 mph 30.1, 2015 7.3, 2021
Maximum Gust 20.0 mph 22.1 mph 39.8 mph, 2015 10.3 mph, 2021
Mean Wind Direction n/a
Rainfall 0.0 mm 32.4 mm (83%) 12.5 mm, 2023
Maximum Hourly Rain n/a 3.6, 2023
Maximum 10-min Rain n/a 1.2, 2023
Maximum Rain Rate n/a 14.4, 2023
Minimum Dew Point 2.4 °C 23:58 0.3 °C 8.7 °C, 2023 -7.5 °C, 2013
Maximum Dew Point 7.2 °C 12:46 5.5 °C 12.6 °C, 2011 -1.6 °C, 2013
Mean Dew Point 3.9 °C 2.7 °C 9.6 °C, 2011 -5.2 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 8.3 °C 3.9 °C 13.0 °C, 2017 -2.6 °C, 2013
Day Maximum (09-21) 13.4 °C 12.3 °C 21.1 °C, 2021 5.6 °C, 2013
Max 10m Temp Rise n/a 12:26 0.4 °C 1, 2022 0.3, 2012
Max 1hr Temp Rise n/a 12:53 1.0 °C 3.9, 2021 0.8, 2012
Max 1hr Hum Rise n/a 22:16 4% 25, 2022 5, 2017
Max 10m Temp Fall n/a 12:06 0.4 °C 1, 2015 0.2, 2017
Max 1hr Temp Fall n/a 21:56 0.9 °C 2.2, 2015 0.9, 2024
Max 1hr Hum Fall n/a 13:13 5% 25, 2015 4, 2024
Max 10m Wind Speed n/a 0.0 mph 21.3, 2015 5, 2021
Minimum Feels-like n/a 0.0 °C 11.2, 2017 -6.1, 2013
Maximum Feels-like n/a 0.0 °C 22.9, 2021 4, 2013
Mean Feels-like n/a 0.0 °C 15.2, 2021 -0.9, 2022
Air-frost Hrs 0 hrs 0.0 hrs 7 hrs, 2013 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.1 °C (-2.3) 8.7 °C (+2.0) 13.8 °C (+6.4), 2021 3.4 °C (-4.0), 2010
Humidity Range 20% 38% 53%, 2015 11%, 2023
Pressure Range 3 hPa 9 hPa 22 hPa, 2015 2 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.6 [5%]165 hrs (146%) [50%] 8 [69%], 2016 0 [0%], 2023
Wet Hours 0 hrs (0%) [0%] 14, 2023 , 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 31st March 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