Daily Report for 24th September 2017

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 10.6 °C (-0.2) 07:14 10.3 °C (-1.5) 14.7 °C (+3.9), 2019 6.0 °C (-4.8), 2018
Maximum Temperature 21.9 °C (+4.2) 15:12 18.3 °C (-1.0) 22.5 °C (+4.8), 2016 13.6 °C (-4.1), 2010
Mean Temperature 16.4 °C (+2.0) 14.2 °C (-1.3) 18.0 °C, 2016 10.6 °C, 2018
Minimum Humidity 44% 15:03 58% 80%, 2019 44%, 2017
Maximum Humidity 95% 07:52 92% 98%, 2012 81%, 2016
Mean Humidity 73% 78% 91%, 2019 64%, 2016
Minimum Pressure 1018 hPa 17:01 1009 hPa 1031 hPa, 2018 985 hPa, 2012
Maximum Pressure 1021 hPa 00:15 1015 hPa 1039 hPa, 2018 996 hPa, 2012
Mean Pressure 1019 hPa 1012 hPa 1036 hPa, 2018 989 hPa, 2012
Mean Wind Speed 3.6 mph (-0.3) 4.5 mph (+0.6) 8.6 mph, 2016 1.3 mph, 2013
Maximum Wind Speed 13.0 mph 12:14 12.9 mph 22.9 mph, 2016 6.0 mph, 2013
Maximum Gust 17.3 mph 11:36 20.0 mph 35.5 mph, 2016 7.6 mph, 2013
Mean Wind Direction ESE
Rainfall 0.0 mm 34.3 mm (86%) 32.0 mm, 2019
Maximum Hourly Rain n/a 10.3, 2019
Maximum 10-min Rain n/a 4.4, 2019
Maximum Rain Rate n/a 66, 2019
Minimum Dew Point 9.1 °C 15:03 7.9 °C 13.5 °C, 2019 3.6 °C, 2018
Maximum Dew Point 13.9 °C 23:25 12.6 °C 17.3 °C, 2013 6.8 °C, 2018
Mean Dew Point 11.0 °C 10.2 °C 15.0 °C, 2019 5.4 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 10.6 °C 07:14 10.5 °C 15.7 °C, 2019 6.1 °C, 2018
Day Maximum (09-21) 21.9 °C 15:12 18.3 °C 22.5 °C, 2016 13.6 °C, 2010
Max 10m Temp Rise 0.7 °C 09:14 0.6 °C 0.9 °C, 2011 0.3 °C, 2010
Max 1hr Temp Rise 3.0 °C 09:35 2.1 °C 4.0 °C, 2011 1.0 °C, 2010
Max 1hr Hum Rise 10% 20:25 11% 19%, 2020 3%, 2010
Max 10m Temp Fall 0.3 °C 00:11 0.6 °C 1.5 °C, 2020 0.2 °C, 2016
Max 1hr Temp Fall 1.4 °C 17:13 1.8 °C 4.1 °C, 2020 0.8 °C, 2010
Max 1hr Hum Fall 13% 09:57 11% 21%, 2014 4%, 2023
Max 10m Wind Speed 9.6 mph 12:37 9.5 mph 18.6 mph, 2016 3.9 mph, 2013
Minimum Feels-like 11.7 °C 07:14 10.2 °C 17.8 °C, 2019 4.1 °C, 2018
Maximum Feels-like 23.4 °C 14:54 20.2 °C 27.2 °C, 2021 15.9 °C, 2018
Mean Feels-like 18.1 °C 15.5 °C 20.9 °C, 2021 10.2 °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 11.3 °C (+4.3) 8.1 °C (+0.4) 12.1 °C (+5.1), 2011 3.4 °C (-3.6), 2024
Humidity Range 51% 34% 51%, 2017 12%, 2023
Pressure Range 3 hPa 6 hPa 13 hPa, 2010 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 9 [82%]103 hrs (86%) [37%] 11 [101%], 2018 0.5 [5%], 2010
Wet Hours 037 hrs (113%) [6.4%] 14, 2019 0, 2009
Cloud Cover am: Sunny
pm: Hazy transitioned to Overcast
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 24th September 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

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Webcam Summary of Cloud Conditions

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Wind rose