Daily Report for 11th September 2026

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 15.6 °C (+3.6) 07:18 14.1 °C (+1.8) 19.3 °C (+7.3), 2023 8.1 °C (-3.9), 2020
Maximum Temperature 21.2 °C (+1.4) 15:58 22.2 °C (+1.7) 25.1 °C (+5.3), 2023 15.3 °C (-4.5), 2024
Mean Temperature 17.9 °C (+2.5) 18.1 °C (+1.8) 21.7 °C, 2023 10.7 °C, 2024
Minimum Humidity 57% 16:52 51% 76%, 2018 37%, 2012
Maximum Humidity 92% 04:15 86% 97%, 2022 79%, 2012
Mean Humidity 77% 71% 84%, 2022 58%, 2012
Minimum Pressure 1016 hPa 01:19 1015 hPa 1034 hPa, 2009 991 hPa, 2017
Maximum Pressure 1025 hPa 23:39 1021 hPa 1038 hPa, 2009 1001 hPa, 2017
Mean Pressure 1020 hPa 1019 hPa 1036 hPa, 2009 994 hPa, 2017
Mean Wind Speed 2.5 mph (-1.4) 4.9 mph (+1.0) 8.3 mph, 2017 2.1 mph, 2020
Maximum Wind Speed 9.9 mph 00:07 13.6 mph 21.5 mph, 2011 7.4 mph, 2014
Maximum Gust 13.8 mph 00:21 22.5 mph 31.7 mph, 2011 9.8 mph, 2014
Mean Wind Direction NW
Rainfall 3.2 mm 21.8 mm (119%) 7.7 mm, 2017
Maximum Hourly Rain 2.2 mm 01:01 5.5 mm, 2017
Maximum 10-min Rain 0.6 mm 00:16 3.5 mm, 2017
Maximum Rain Rate 3.6 mm/h 00:33 53 mm/h, 2017
Minimum Dew Point 11.9 °C 17:50 10.2 °C 16.1 °C, 2023 1.3 °C, 2012
Maximum Dew Point 15.4 °C 10:19 14.8 °C 18.3 °C, 2023 9.9 °C, 2024
Mean Dew Point 13.7 °C 12.4 °C 17.5 °C, 2023 6.8 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 15.6 °C 07:17 14.6 °C 19.3 °C, 2023 8.1 °C, 2020
Day Maximum (09-21) 21.2 °C 16:07 22.0 °C 25.1 °C, 2023 15.3 °C, 2024
Max 10m Temp Rise 0.5 °C 09:20 0.6 °C 1.0 °C, 2016 0.3 °C, 2018
Max 1hr Temp Rise 1.5 °C 08:57 2.2 °C 3.7 °C, 2016 1.3 °C, 2018
Max 1hr Hum Rise 10% 18:50 9% 23%, 2025 4%, 2010
Max 10m Temp Fall 0.4 °C 11:07 0.6 °C 1.6 °C, 2025 0.2 °C, 2010
Max 1hr Temp Fall 1.5 °C 20:03 1.9 °C 4.3 °C, 2025 1.1 °C, 2010
Max 1hr Hum Fall 11% 11:32 11% 28%, 2016 4%, 2018
Max 10m Wind Speed 6.7 mph 00:27 10.0 mph 14.4 mph, 2017 4.3 mph, 2014
Minimum Feels-like 17.9 °C 23:58 15.9 °C 24.6 °C, 2023 5.1 °C, 2024
Maximum Feels-like 24.2 °C 15:59 25.2 °C 30.8 °C, 2023 15.8 °C, 2024
Mean Feels-like 21.1 °C 20.7 °C 27.3 °C, 2023 10.0 °C, 2024
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Minimum PM2.5 1 15:35 1 1, 2026 0, 2021
Maximum PM2.5 12 22:20 11 12, 2026 12, 2026
Mean PM2.5 3 3 3, 2026 3, 2026
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.6 °C (-2.2) 8.1 °C (-0.1) 12.5 °C (+4.7), 2016 4.5 °C (-3.3), 2010
Humidity Range 35% 35% 51%, 2015 13%, 2019
Pressure Range 9 hPa 6 hPa 10 hPa, 2017 2 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 5.1 [43%]61 hrs (107%) [46%] 11.7 [100%], 2016 0 [0%], 2014
Wet Hours 4
[Mean rain rate: 0.8 mm/h]		20 hrs (133%) [7.6%] 4, 2013 0, 2009
Cloud Cover unknown
Events None
Comments data is awaiting quality control from site operator
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 18.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 11th September 2026.
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.
View monthly summary

Daily Graph of Conditions

day graph

Webcam Summary of Cloud Conditions

daycamsumFull resolution individual images at up-to 5 minute intervals

Wind rose