Daily Report for 18th August 2026

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 18.2 °C (+4.1) 04:57 15.7 °C (+1.4) 20.0 °C (+5.9), 2012 11.4 °C (-2.7), 2014
Maximum Temperature 25.4 °C (+3.0) 15:48 28.7 °C (+5.9) 30.0 °C (+7.6), 2012 17.1 °C (-5.3), 2011
Mean Temperature 21.8 °C (+3.6) 22.5 °C (+3.6) 25.0 °C, 2012 13.7 °C, 2011
Minimum Humidity 51% 16:49 36% 72%, 2023 40%, 2012
Maximum Humidity 81% 08:10 77% 95%, 2022 71%, 2015
Mean Humidity 67% 55% 86%, 2023 53%, 2012
Minimum Pressure 1011 hPa 18:30 1017 hPa 1020 hPa, 2018 1003 hPa, 2019
Maximum Pressure 1014 hPa 00:00 1021 hPa 1024 hPa, 2025 1010 hPa, 2010
Mean Pressure 1012 hPa 1019 hPa 1022 hPa, 2025 1006 hPa, 2019
Mean Wind Speed 6.1 mph (+2.1) 3.8 mph (-0.2) 6.3 mph, 2017 2.3 mph, 2024
Maximum Wind Speed 12.6 mph 12:49 12.1 mph 16.1 mph, 2019 8.8 mph, 2024
Maximum Gust 19.6 mph 03:13 18.2 mph 26.5 mph, 2019 13.5 mph, 2024
Mean Wind Direction NW
Rainfall 0.6 mm 0.6 mm (2%) 14.6 mm, 2011
Maximum Hourly Rain 0.6 mm 03:50 9.9 mm, 2017
Maximum 10-min Rain 0.6 mm 03:50 5.9 mm, 2017
Maximum Rain Rate 2.4 mm/h 03:50 84 mm/h, 2023
Minimum Dew Point 11.9 °C 03:08 9.7 °C 15.6 °C, 2022 5.6 °C, 2014
Maximum Dew Point 17.8 °C 11:50 15.0 °C 18.6 °C, 2023 10.5 °C, 2014
Mean Dew Point 15.2 °C 12.3 °C 17.2 °C, 2023 8.6 °C, 2014
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 18.2 °C 05:00 15.8 °C 20.0 °C, 2012 11.4 °C, 2014
Day Maximum (09-21) 25.4 °C 15:48 28.7 °C 30.0 °C, 2012 17.1 °C, 2011
Max 10m Temp Rise 0.4 °C 11:48 0.8 °C 0.8 °C, 2017 0.3 °C, 2011
Max 1hr Temp Rise 1.3 °C 11:50 3.2 °C 2.8 °C, 2010 1.0 °C, 2018
Max 1hr Hum Rise 18% 04:08 12% 20%, 2017 4%, 2021
Max 10m Temp Fall 0.8 °C 03:23 0.8 °C 2.9 °C, 2017 0.2 °C, 2015
Max 1hr Temp Fall 1.7 °C 04:02 2.5 °C 4.4 °C, 2017 0.6 °C, 2015
Max 1hr Hum Fall 10% 14:52 12% 15%, 2016 6%, 2015
Max 10m Wind Speed 9.1 mph 14:55 8.7 mph 12.3 mph, 2019 6.1 mph, 2009
Minimum Feels-like 21.7 °C 04:41 17.5 °C 22.9 °C, 2012 11.5 °C, 2014
Maximum Feels-like 29.7 °C 14:48 31.6 °C 34.9 °C, 2012 18.7 °C, 2011
Mean Feels-like 25.9 °C 25.1 °C 28.7 °C, 2012 15.3 °C, 2011
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Minimum PM2.5 3 01:37 3 3, 2026 0, 2021
Maximum PM2.5 15 13:35 13 15, 2026 15, 2026
Mean PM2.5 7 6 7, 2026 7, 2026
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 7.2 °C (-1.1) 13.0 °C (+4.5) 10.0 °C (+1.7), 2012 4.9 °C (-3.4), 2015
Humidity Range 30% 42% 50%, 2010 20%, 2018
Pressure Range 4 hPa 5 hPa 9 hPa, 2023 2 hPa, 2020
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.1 [1%]186 hrs (168%) [76%] 12 [91%], 2012 0 [0%], 2011
Wet Hours 1
[Mean rain rate: 0.6 mm/h]		1 hrs (5%) [0.2%] 3, 2019 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 23.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 18th August 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.
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Daily Graph of Conditions

day graph

Webcam Summary of Cloud Conditions

daycamsumFull resolution individual images at up-to 5 minute intervals

Wind rose