Daily Report for 13th September 2017

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 11.2 °C (-0.6) 23:57 11.1 °C (-1.1) 17.7 °C (+5.9), 2016 6.8 °C (-5.0), 2018
Maximum Temperature 17.3 °C (-2.1) 11:56 19.2 °C (-1.1) 32.0 °C (+12.6), 2016 16.3 °C (-3.1), 2009
Mean Temperature 14.3 °C (-1.4) 15.1 °C (-1.1) 24.8 °C, 2016 13.2 °C, 2009
Minimum Humidity 57% 11:51 58% 91%, 2013 36%, 2016
Maximum Humidity 95% 00:43 91% 98%, 2013 78%, 2011
Mean Humidity 71% 76% 96%, 2013 62%, 2016
Minimum Pressure 993 hPa 02:46 1004 hPa 1030 hPa, 2019 993 hPa, 2017
Maximum Pressure 1002 hPa 23:00 1012 hPa 1037 hPa, 2019 1002 hPa, 2017
Mean Pressure 999 hPa 1008 hPa 1034 hPa, 2019 999 hPa, 2017
Mean Wind Speed 10.2 mph (+6.3) 5.4 mph (+1.5) 10.2 mph, 2017 2.1 mph, 2018
Maximum Wind Speed 24.2 mph 03:27 14.8 mph 24.2 mph, 2017 7.8 mph, 2013
Maximum Gust 41.5 mph 04:00 23.1 mph 41.5 mph, 2017 12.7 mph, 2013
Mean Wind Direction WSW
Rainfall 2.6 mm 29.2 mm (135%) 32.0 mm, 2013
Maximum Hourly Rain 2.0 mm 14:13 9.0 mm, 2013
Maximum 10-min Rain 2.0 mm 14:13 2.2 mm, 2013
Maximum Rain Rate 40 mm/h 14:10 42 mm/h, 2013
Minimum Dew Point 6.6 °C 20:13 8.3 °C 14.7 °C, 2016 4.4 °C, 2012
Maximum Dew Point 14.0 °C 01:05 13.6 °C 17.7 °C, 2016 9.0 °C, 2012
Mean Dew Point 9.0 °C 10.7 °C 16.3 °C, 2016 6.3 °C, 2012
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 12.4 °C * 07:41 11.4 °C 17.7 °C, 2016 6.8 °C, 2018
Day Maximum (09-21) 17.3 °C 11:56 19.2 °C 32.2 °C, 2016 16.3 °C, 2009
Max 10m Temp Rise 0.6 °C 15:11 0.6 °C 1.1 °C, 2016 0.2 °C, 2013
Max 1hr Temp Rise 2.3 °C 15:24 2.1 °C 3.9 °C, 2018 0.8 °C, 2013
Max 1hr Hum Rise 21% 14:41 12% 32%, 2019 3%, 2013
Max 10m Temp Fall 1.6 °C 14:14 0.7 °C 1.6 °C, 2017 0.3 °C, 2010
Max 1hr Temp Fall 2.8 °C 14:30 1.8 °C 2.8 °C, 2017 0.9 °C, 2010
Max 1hr Hum Fall 22% 15:42 10% 22%, 2017 1%, 2013
Max 10m Wind Speed 18.4 mph 04:03 11.0 mph 18.4 mph, 2017 6.1 mph, 2022
Minimum Feels-like 11.2 °C 23:55 11.7 °C 23.4 °C, 2016 5.5 °C, 2012
Maximum Feels-like 18.2 °C 01:05 21.5 °C 36.9 °C, 2016 17.6 °C, 2009
Mean Feels-like 15.2 °C 16.8 °C 29.6 °C, 2016 13.1 °C, 2012
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 6.1 °C (-1.5) 8.1 °C (+0.0) 14.3 °C (+6.7), 2016 4.3 °C (-3.3), 2022
Humidity Range 38% 33% 56%, 2018 7%, 2013
Pressure Range 9 hPa 8 hPa 10 hPa, 2015 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 9 [77%]59 hrs (89%) [38%] 11.6 [100%], 2019 0 [0%], 2013
Wet Hours 1
[Mean rain rate: 2.6 mm/h]
29 hrs (160%) [9.1%] 15, 2013 0, 2009
Cloud Cover am: Sunny transitioned to Mostly Sunny
pm: Mostly Sunny with periods of Partly Cloudy
Events None
Comments day Showers
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 13th 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.
View monthly summary

Daily Graph of Conditions

day graph

Webcam Summary of Cloud Conditions

daycamsumLarge resolution version

Wind rose