Daily Report for 27th September 2023

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 13.7 °C (+3.2) 07:10 14.3 °C (+2.7) 13.7 °C (+3.2), 2023 5.8 °C (-4.7), 2024
Maximum Temperature 21.2 °C (+3.9) 14:41 23.6 °C (+4.5) 23.6 °C (+6.3), 2018 12.4 °C (-4.9), 2024
Mean Temperature 17.8 °C (+3.5) 18.8 °C (+3.6) 17.8 °C, 2023 10.4 °C, 2022
Minimum Humidity 70% 14:53 61% 80%, 2010 29%, 2018
Maximum Humidity 96% 07:49 94% 98%, 2010 81%, 2020
Mean Humidity 84% 80% 91%, 2010 62%, 2018
Minimum Pressure 1009 hPa 19:40 1012 hPa 1031 hPa, 2015 991 hPa, 2024
Maximum Pressure 1020 hPa 02:46 1018 hPa 1036 hPa, 2015 1005 hPa, 2022
Mean Pressure 1015 hPa 1015 hPa 1033 hPa, 2015 1002 hPa, 2024
Mean Wind Speed 5.6 mph (+1.7) 4.2 mph (+0.3) 7.1 mph, 2019 0.8 mph, 2014
Maximum Wind Speed 16.5 mph 19:44 12.8 mph 20.8 mph, 2016 4.9 mph, 2014
Maximum Gust 31.1 mph 20:36 19.8 mph 33.9 mph, 2016 7.8 mph, 2014
Mean Wind Direction SW
Rainfall 0.0 mm 46.1 mm (102%) 13.9 mm, 2017
Maximum Hourly Rain n/a 7.7, 2024
Maximum 10-min Rain n/a 3.5, 2019
Maximum Rain Rate n/a 92, 2019
Minimum Dew Point 12.7 °C 06:35 12.5 °C 12.7 °C, 2023 3.8 °C, 2024
Maximum Dew Point 16.8 °C 13:28 17.3 °C 16.8 °C, 2023 8.9 °C, 2020
Mean Dew Point 14.9 °C 15.0 °C 14.9 °C, 2023 7.5 °C, 2020
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 13.7 °C 07:10 14.7 °C 16.1 °C, 2021 8.2 °C, 2022
Day Maximum (09-21) 21.2 °C 14:43 23.6 °C 23.6 °C, 2018 12.4 °C, 2024
Max 10m Temp Rise 0.7 °C 11:09 0.6 °C 0.8 °C, 2018 0.3 °C, 2011
Max 1hr Temp Rise 2.5 °C 11:45 2.4 °C 3.3 °C, 2018 1.2 °C, 2024
Max 1hr Hum Rise 7% 15:57 9% 17%, 2012 2%, 2020
Max 10m Temp Fall 0.5 °C 20:40 0.5 °C 1.2 °C, 2021 0.1 °C, 2010
Max 1hr Temp Fall 2.1 °C 21:30 1.8 °C 3.1 °C, 2018 0.4 °C, 2010
Max 1hr Hum Fall 11% 11:28 11% 19%, 2018 4%, 2020
Max 10m Wind Speed 13.3 mph 20:52 9.4 mph 14.5 mph, 2016 3.7 mph, 2014
Minimum Feels-like 16.4 °C 07:10 17.0 °C 16.4 °C, 2023 3.4 °C, 2024
Maximum Feels-like 26.2 °C 13:32 28.8 °C 26.2 °C, 2023 13.9 °C, 2022
Mean Feels-like 21.7 °C 22.9 °C 21.7 °C, 2023 10.0 °C, 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 7.5 °C (+0.7) 9.3 °C (+1.7) 13.3 °C (+6.5), 2018 3.1 °C (-3.7), 2020
Humidity Range 26% 33% 61%, 2018 7%, 2020
Pressure Range 11 hPa 6 hPa 27 hPa, 2024 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 1 [9%]150 hrs (112%) [48%] 10.8 [101%], 2018 0 [0%], 2020
Wet Hours 026 hrs (69%) [3.9%] 5, 2024 0, 2009
Cloud Cover unknown
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 17.9 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 27th September 2023.
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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