Daily Report for 29th September 2017

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 12.8 °C (+2.5) 23:55 10.9 °C (-0.7) 14.0 °C (+3.7), 2011 4.4 °C (-5.9), 2024
Maximum Temperature 18.5 °C (+1.4) 11:54 18.5 °C (-0.5) 26.9 °C (+9.8), 2011 14.6 °C (-2.5), 2024
Mean Temperature 16.2 °C (+2.0) 14.5 °C (-0.6) 19.6 °C, 2011 9.8 °C, 2024
Minimum Humidity 78% 12:05 60% 83%, 2014 42%, 2011
Maximum Humidity 96% 05:37 92% 96%, 2010 84%, 2016
Mean Humidity 88% 79% 90%, 2019 70%, 2016
Minimum Pressure 1014 hPa 11:16 1010 hPa 1032 hPa, 2015 993 hPa, 2019
Maximum Pressure 1018 hPa 00:45 1016 hPa 1036 hPa, 2015 1008 hPa, 2013
Mean Pressure 1016 hPa 1013 hPa 1034 hPa, 2015 998 hPa, 2019
Mean Wind Speed 4.2 mph (+0.3) 4.4 mph (+0.5) 11.4 mph, 2016 0.7 mph, 2025
Maximum Wind Speed 13.4 mph 13:53 12.4 mph 22.7 mph, 2016 5.6 mph, 2025
Maximum Gust 19.6 mph 11:46 19.2 mph 40.3 mph, 2016 9.2 mph, 2025
Mean Wind Direction SW
Rainfall 6.2 mm 63.2 mm (131%) 11.7 mm, 2010
Maximum Hourly Rain 2.2 mm 04:51 3.5 mm, 2010
Maximum 10-min Rain 1.8 mm 14:30 1.8 mm, 2017
Maximum Rain Rate 26 mm/h 14:25 26 mm/h, 2017
Minimum Dew Point 10.9 °C 23:55 8.5 °C 11.5 °C, 2014 2.7 °C, 2012
Maximum Dew Point 16.5 °C 08:48 13.1 °C 17.4 °C, 2011 8.2 °C, 2018
Mean Dew Point 14.1 °C 10.8 °C 14.1 °C, 2017 6.0 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 14.1 °C * 22:48 11.1 °C 16.8 °C, 2016 4.4 °C, 2024
Day Maximum (09-21) 18.5 °C 11:54 18.5 °C 26.9 °C, 2011 14.6 °C, 2024
Max 10m Temp Rise 0.3 °C 10:57 0.6 °C 0.9 °C, 2018 0.3 °C, 2010
Max 1hr Temp Rise 1.0 °C 11:25 2.0 °C 3.9 °C, 2025 0.8 °C, 2019
Max 1hr Hum Rise 7% 15:00 11% 13%, 2018 3%, 2013
Max 10m Temp Fall 1.0 °C 14:36 0.6 °C 1.0 °C, 2017 0.2 °C, 2014
Max 1hr Temp Fall 2.3 °C 15:13 1.7 °C 3.4 °C, 2018 0.9 °C, 2014
Max 1hr Hum Fall 10% 12:05 11% 18%, 2012 6%, 2019
Max 10m Wind Speed 10.0 mph 12:08 9.1 mph 17.4 mph, 2016 4.0 mph, 2025
Minimum Feels-like 14.5 °C 23:52 11.2 °C 16.1 °C, 2011 3.5 °C, 2022
Maximum Feels-like 22.8 °C 11:25 20.7 °C 30.0 °C, 2011 15.2 °C, 2012
Mean Feels-like 19.7 °C 16.2 °C 22.8 °C, 2011 10.2 °C, 2024
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.7 °C (-1.1) 7.6 °C (+0.2) 12.9 °C (+6.1), 2011 4.1 °C (-2.7), 2013
Humidity Range 18% 32% 54%, 2011 13%, 2014
Pressure Range 4 hPa 6 hPa 19 hPa, 2024 2 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0.3 [3%]112 hrs (79%) [34%] 10.61 [100%], 2011 0.1 [1%], 2010
Wet Hours 4
[Mean rain rate: 1.6 mm/h]		53 hrs (132%) [7.5%] 10, 2010 0, 2009
Cloud Cover Mostly Cloudy or Overcast
Events None
Comments am Rain, 1430 Shower
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 29th 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

day graph

Webcam Summary of Cloud Conditions

daycamsumLarge resolution version

Wind rose