Daily Report for 25th August 2017

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.2 °C (-2.4) 06:21 13.6 °C (-0.6) 18.5 °C (+4.9), 2016 7.8 °C (-5.8), 2018
Maximum Temperature 24.6 °C (+2.7) 17:47 21.5 °C (-1.1) 31.9 °C (+10.0), 2019 16.8 °C (-5.1), 2014
Mean Temperature 18.2 °C (+0.2) 17.4 °C (-0.9) 23.5 °C, 2019 12.5 °C, 2018
Minimum Humidity 44% 18:12 51% 80%, 2022 32%, 2019
Maximum Humidity 85% 07:50 82% 98%, 2013 83%, 2023
Mean Humidity 64% 67% 90%, 2022 55%, 2025
Minimum Pressure 1014 hPa 18:51 1014 hPa 1024 hPa, 2021 998 hPa, 2020
Maximum Pressure 1020 hPa 09:05 1019 hPa 1030 hPa, 2021 1006 hPa, 2012
Mean Pressure 1018 hPa 1017 hPa 1027 hPa, 2021 1002 hPa, 2012
Mean Wind Speed 1.0 mph (-3.0) 4.0 mph (-0.0) 9.8 mph, 2020 1.0 mph, 2017
Maximum Wind Speed 7.3 mph 13:18 11.5 mph 26.5 mph, 2020 6.9 mph, 2014
Maximum Gust 10.5 mph 16:18 17.6 mph 39.2 mph, 2020 10.2 mph, 2014
Mean Wind Direction SW
Rainfall 0.0 mm 77.2 mm (177%) 38.5 mm, 2014
Maximum Hourly Rain n/a 9.2, 2014
Maximum 10-min Rain n/a 3.3, 2014
Maximum Rain Rate n/a 48, 2022
Minimum Dew Point 8.2 °C 05:37 8.2 °C 15.7 °C, 2016 6.6 °C, 2018
Maximum Dew Point 12.8 °C 09:15 13.4 °C 19.0 °C, 2016 11.6 °C, 2018
Mean Dew Point 10.8 °C 10.9 °C 17.1 °C, 2016 8.4 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 11.2 °C 06:21 13.7 °C 18.5 °C, 2016 7.8 °C, 2018
Day Maximum (09-21) 24.6 °C 17:47 21.5 °C 31.9 °C, 2019 16.8 °C, 2014
Max 10m Temp Rise 0.6 °C 08:14 0.6 °C 0.9 °C, 2025 0.2 °C, 2014
Max 1hr Temp Rise 2.8 °C 08:47 2.1 °C 4.7 °C, 2025 1.0 °C, 2014
Max 1hr Hum Rise 9% 21:00 8% 24%, 2009 5%, 2022
Max 10m Temp Fall 0.7 °C 20:18 0.6 °C 1.3 °C, 2018 0.2 °C, 2014
Max 1hr Temp Fall 2.7 °C 20:13 1.8 °C 3.3 °C, 2009 0.4 °C, 2014
Max 1hr Hum Fall 12% 09:43 9% 19%, 2025 1%, 2014
Max 10m Wind Speed 4.6 mph 16:32 8.5 mph 17.6 mph, 2020 4.6 mph, 2017
Minimum Feels-like 11.7 °C 06:08 14.7 °C 22.9 °C, 2016 5.0 °C, 2018
Maximum Feels-like 26.8 °C 17:39 23.7 °C 36.0 °C, 2019 18.9 °C, 2018
Mean Feels-like 19.9 °C 19.2 °C 27.8 °C, 2016 12.5 °C, 2018
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 13.4 °C (+5.1) 7.9 °C (-0.6) 16.1 °C (+7.7), 2019 3.3 °C (-5.0), 2014
Humidity Range 41% 31% 57%, 2019 16%, 2022
Pressure Range 6 hPa 5 hPa 15 hPa, 2020 2 hPa, 2019
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 12.5 [98%]135 hrs (89%) [40%] 12.8 [100%], 2025 0 [0%], 2014
Wet Hours 040 hrs (129%) [6.6%] 16, 2014 0, 2017
Cloud Cover Sunny with periods of Mostly Sunny
Events Maximum possible sunshine
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 25th August 2017.
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

daycamsumLarge resolution version

Wind rose