Daily Report for 20th June 2009

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.2 °C (-1.1) 06:19 10.4 °C (-1.2) 17.6 °C (+5.3), 2017 7.3 °C (-5.0), 2010
Maximum Temperature 18.3 °C (-3.1) 13:16 19.6 °C (-0.9) 30.3 °C (+8.9), 2017 18.2 °C (-3.2), 2021
Mean Temperature 14.6 °C (-2.1) 14.8 °C (-1.1) 23.6 °C, 2017 12.4 °C, 2010
Minimum Humidity 53% 15:12 49% 80%, 2021 36%, 2012
Maximum Humidity 81% 08:28 86% 96%, 2021 75%, 2010
Mean Humidity 66% 69% 90%, 2021 58%, 2012
Minimum Pressure 1022 hPa 10:35 1013 hPa 1022 hPa, 2009 1008 hPa, 2023
Maximum Pressure 1024 hPa 23:54 1018 hPa 1025 hPa, 2024 1012 hPa, 2021
Mean Pressure 1023 hPa 1016 hPa 1023 hPa, 2009 1010 hPa, 2023
Mean Wind Speed 3.6 mph (-0.8) 4.2 mph (-0.2) 6.7 mph, 2018 1.8 mph, 2014
Maximum Wind Speed n/a 0.0 mph 15.1, 2023 7.3, 2010
Maximum Gust 18.0 mph 19.8 mph 23.0 mph, 2023 10.3 mph, 2010
Mean Wind Direction n/a
Rainfall trace 34.7 mm (111%) 15.2, 2016
Maximum Hourly Rain n/a 5.5, 2016
Maximum 10-min Rain n/a 1.5, 2015
Maximum Rain Rate n/a 42, 2015
Minimum Dew Point 6.0 °C 00:09 5.9 °C 13.7 °C, 2023 2.3 °C, 2010
Maximum Dew Point 10.5 °C 15:23 11.4 °C 18.4 °C, 2023 7.0 °C, 2010
Mean Dew Point 8.3 °C 8.6 °C 16.2 °C, 2023 5.0 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 11.2 °C 10.6 °C 17.6 °C, 2017 7.3 °C, 2010
Day Maximum (09-21) 18.3 °C 19.6 °C 30.3 °C, 2017 18.2 °C, 2021
Max 10m Temp Rise 0.8 °C 13:09 0.8 °C 1.5 °C, 2012 0.4 °C, 2015
Max 1hr Temp Rise 2.4 °C 13:10 2.4 °C 4.2 °C, 2012 1.4 °C, 2021
Max 1hr Hum Rise 13% 17:35 9% 20%, 2024 4%, 2021
Max 10m Temp Fall 0.5 °C 17:16 0.6 °C 0.7 °C, 2012 0.4 °C, 2010
Max 1hr Temp Fall 1.4 °C 22:08 1.7 °C 2.4 °C, 2017 1.2 °C, 2019
Max 1hr Hum Fall 11% 13:37 12% 17%, 2012 4%, 2015
Max 10m Wind Speed n/a 0.0 mph 11.2, 2023 5.9, 2017
Minimum Feels-like n/a 0.0 °C 20.6, 2017 6.2, 2010
Maximum Feels-like n/a 0.0 °C 34.6, 2017 18.9, 2010
Mean Feels-like n/a 0.0 °C 27.4, 2017 12.0, 2010
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 7.1 °C (-1.9) 9.2 °C (+0.3) 13.8 °C (+4.8), 2024 5.8 °C (-3.2), 2021
Humidity Range 28% 38% 52%, 2012 16%, 2021
Pressure Range 2 hPa 5 hPa 8 hPa, 2016 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 3 [20%]110 hrs (85%) [37%] 14 [93%], 2022 0 [0%], 2021
Wet Hours 133 hrs (135%) [6.9%] 8, 2016 0, 2010
Cloud Cover not available
Events None
Comments 04-06 SLight Rain//DrizzleShowers, 17-1730 SLight Rain
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 June 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