Daily Report for 10th September 2012

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 16.8 °C (+4.8) 06:30 12.1 °C (-0.2) 18.0 °C (+6.0), 2023 8.8 °C (-3.2), 2013
Maximum Temperature 20.7 °C (+0.9) 13:09 23.1 °C (+2.6) 30.4 °C (+10.6), 2023 16.5 °C (-3.3), 2013
Mean Temperature 18.4 °C (+2.9) 17.4 °C (+1.2) 23.4 °C, 2023 12.3 °C, 2013
Minimum Humidity 64% 15:49 44% 83%, 2016 37%, 2015
Maximum Humidity 84% 04:05 86% 96%, 2013 84%, 2012
Mean Humidity 74% 66% 93%, 2016 68%, 2020
Minimum Pressure 1009 hPa 03:33 1020 hPa 1033 hPa, 2009 992 hPa, 2017
Maximum Pressure 1011 hPa 11:45 1024 hPa 1038 hPa, 2009 1003 hPa, 2017
Mean Pressure 1010 hPa 1022 hPa 1036 hPa, 2009 999 hPa, 2017
Mean Wind Speed 9.2 mph (+5.3) 3.9 mph (+0.0) 9.2 mph, 2012 0.6 mph, 2020
Maximum Wind Speed 14.7 mph 13:00 10.1 mph 20.0 mph, 2017 5.6 mph, 2020
Maximum Gust 24.2 mph 10:51 14.8 mph 32.3 mph, 2017 10.4 mph, 2020
Mean Wind Direction SW
Rainfall 0.0 mm 0.0 mm (0%) 4.5 mm, 2021
Maximum Hourly Rain n/a 3.4, 2021
Maximum 10-min Rain n/a 2.9, 2021
Maximum Rain Rate n/a 30, 2021
Minimum Dew Point 12.3 °C 11:59 7.1 °C 16.5 °C, 2023 4.8 °C, 2015
Maximum Dew Point 15.2 °C 09:39 13.3 °C 22.2 °C, 2023 10.0 °C, 2020
Mean Dew Point 13.5 °C 10.2 °C 18.7 °C, 2023 8.2 °C, 2009
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 16.8 °C 06:30 12.1 °C 18.0 °C, 2023 8.8 °C, 2013
Day Maximum (09-21) 20.7 °C 13:10 23.1 °C 30.4 °C, 2023 16.5 °C, 2013
Max 10m Temp Rise 0.7 °C 09:39 0.7 °C 1.0 °C, 2013 0.2 °C, 2016
Max 1hr Temp Rise 1.8 °C 09:49 3.1 °C 3.6 °C, 2019 0.6 °C, 2016
Max 1hr Hum Rise 5% 18:14 10% 12%, 2017 4%, 2010
Max 10m Temp Fall 0.8 °C 17:47 0.6 °C 1.0 °C, 2024 0.2 °C, 2010
Max 1hr Temp Fall 1.1 °C 20:09 2.2 °C 3.6 °C, 2024 0.7 °C, 2010
Max 1hr Hum Fall 9% 10:06 13% 19%, 2015 3%, 2016
Max 10m Wind Speed 11.6 mph 13:21 7.5 mph 14.5 mph, 2017 3.1 mph, 2020
Minimum Feels-like 19.3 °C 00:20 12.9 °C 22.9 °C, 2023 6.0 °C, 2013
Maximum Feels-like 24.4 °C 13:02 24.9 °C 39.8 °C, 2023 17.0 °C, 2013
Mean Feels-like 21.5 °C 19.0 °C 30.0 °C, 2023 12.5 °C, 2013
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 3.9 °C (-3.9) 11.0 °C (+2.9) 12.4 °C (+4.6), 2023 3.3 °C (-4.5), 2025
Humidity Range 20% 42% 55%, 2015 10%, 2016
Pressure Range 2 hPa 5 hPa 12 hPa, 2025 2 hPa, 2012
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 1.5 [13%]77 hrs (149%) [64%] 11 [94%], 2015 0 [0%], 2016
Wet Hours 00.1 hrs (1%) [0%] 7, 2016 0, 2009
Cloud Cover Mostly Cloudy
Events None
Comments possible 03-04 Showers
Extra Comments
Issues 10th-11th, 1330-08 Data Loss (Wind: total; Other: partial). Some glitchy periods reconstructed.
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 10th September 2012.
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

daycamsum

Wind rose