Daily Report for 13th April 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 7.3 °C (+1.5) 23:56 7.2 °C (+1.5) 12.1 °C (+6.3), 2024 -0.6 °C (-6.4), 2021
Maximum Temperature 17.0 °C (+2.9) 17:06 15.1 °C (+1.5) 20.8 °C (+6.7), 2024 8.8 °C (-5.3), 2019
Mean Temperature 11.6 °C (+2.2) 10.5 °C (+1.5) 15.7 °C, 2024 4.8 °C, 2019
Minimum Humidity 54% 18:46 59% 78%, 2018 39%, 2016
Maximum Humidity 97% 05:30 92% 97%, 2009 71%, 2017
Mean Humidity 83% 77% 87%, 2013 54%, 2016
Minimum Pressure 1009 hPa 16:35 1010 hPa 1032 hPa, 2021 995 hPa, 2023
Maximum Pressure 1014 hPa 00:05 1016 hPa 1034 hPa, 2021 1006 hPa, 2012
Mean Pressure 1012 hPa 1013 hPa 1034 hPa, 2021 1002 hPa, 2023
Mean Wind Speed 3.3 mph (-1.6) 4.2 mph (-0.7) 9.6 mph, 2020 1.5 mph, 2016
Maximum Wind Speed n/a 0.0 mph 19.4, 2020 7.4, 2012
Maximum Gust 17.0 mph 18.8 mph 27.6 mph, 2020 10.0 mph, 2012
Mean Wind Direction n/a
Rainfall trace 8.8 mm (48%) 6.5, 2013
Maximum Hourly Rain n/a 2.1, 2013
Maximum 10-min Rain n/a 1.2, 2012
Maximum Rain Rate n/a 17, 2013
Minimum Dew Point 3.3 °C 23:56 3.5 °C 9.1 °C, 2022 -4.2 °C, 2021
Maximum Dew Point 12.5 °C 13:02 8.9 °C 13.4 °C, 2024 2.9 °C, 2011
Mean Dew Point 8.5 °C 6.3 °C 11.0 °C, 2024 -0.5 °C, 2021
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 9.6 °C * 7.4 °C 12.2 °C, 2024 -0.6 °C, 2021
Day Maximum (09-21) 17.0 °C 15.1 °C 20.8 °C, 2024 8.8 °C, 2019
Max 10m Temp Rise 0.8 °C 13:02 0.3 °C 1.2 °C, 2021 0.3 °C, 2018
Max 1hr Temp Rise 3.0 °C 13:06 0.8 °C 5.1 °C, 2021 1.3 °C, 2018
Max 1hr Hum Rise 7% 21:43 2% 25%, 2023 3%, 2017
Max 10m Temp Fall 0.5 °C 09:34 0.2 °C 1.3 °C, 2019 0.2 °C, 2018
Max 1hr Temp Fall 2.1 °C 21:35 0.5 °C 2.7 °C, 2019 0.7 °C, 2018
Max 1hr Hum Fall 13% 17:15 3% 25%, 2019 5%, 2018
Max 10m Wind Speed n/a 0.0 mph 14.5, 2020 6.1, 2012
Minimum Feels-like n/a 0.0 °C 12.9, 2024 -2.9, 2019
Maximum Feels-like n/a 0.0 °C 22.8, 2024 8.6, 2019
Mean Feels-like n/a 0.0 °C 17.4, 2024 2.5, 2019
Air-frost Hrs 0 hrs 0 hrs 5 hrs, 2021 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 9.7 °C (+1.4) 7.9 °C (-0.1) 12.5 °C (+4.2), 2021 5.6 °C (-2.7), 2018
Humidity Range 43% 33% 55%, 2012 17%, 2018
Pressure Range 5 hPa 7 hPa 13 hPa, 2020 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 5 [41%]63 hrs (94%) [40%] 12.2 [99%], 2014 0 [0%], 2018
Wet Hours 0.217 hrs (83%) [5.3%] 7, 2013 0, 2010
Cloud Cover not available
Events None
Comments ~Wet Ground observed on awakening at 1100 -
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 13th April 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