Daily Report for 12th January 2017

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 0.9 °C (-2.1) 18:15 2.7 °C (-0.4) 8.0 °C (+5.0), 2023 -0.9 °C (-3.9), 2014
Maximum Temperature 6.8 °C (-1.0) 11:21 8.2 °C (+0.3) 12.5 °C (+4.7), 2012 1.5 °C (-6.3), 2010
Mean Temperature 4.6 °C (-1.6) 5.6 °C (-0.0) 10.6 °C, 2023 0.7 °C, 2010
Minimum Humidity 62% 00:12 70% 87%, 2010 55%, 2013
Maximum Humidity 87% 18:42 84% 98%, 2010 87%, 2017
Mean Humidity 75% 78% 94%, 2014 75%, 2017
Minimum Pressure 992 hPa 18:01 1018 hPa 1037 hPa, 2022 989 hPa, 2016
Maximum Pressure 1014 hPa 01:06 1026 hPa 1043 hPa, 2022 1006 hPa, 2023
Mean Pressure 1003 hPa 1022 hPa 1041 hPa, 2022 997 hPa, 2016
Mean Wind Speed 5.4 mph (+0.2) 4.2 mph (-1.0) 11.3 mph, 2023 0.3 mph, 2022
Maximum Wind Speed 17.0 mph 21:44 11.7 mph 25.8 mph, 2023 5.4 mph, 2022
Maximum Gust 24.1 mph 21:44 17.4 mph 36.9 mph, 2020 16.1 mph, 2010
Mean Wind Direction W
Rainfall / Snow-melt approx. 15.9 mm 34.3 mm (150%) 15.9 mm, 2017
Maximum Hourly Rain 4.6 mm 16:46 4.6 mm, 2017
Maximum 10-min Rain 1.0 mm 16:04 1.0 mm, 2017
Maximum Rain Rate 18 mm/h 16:52 18 mm/h, 2017
Minimum Dew Point -2.5 °C 23:55 -0.9 °C 4.4 °C, 2023 -4.1 °C, 2013
Maximum Dew Point 3.1 °C 12:56 4.7 °C 11.4 °C, 2011 0.7 °C, 2010
Mean Dew Point 0.4 °C 2.0 °C 8.5 °C, 2023 -0.3 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 5.5 °C * 04:00 4.1 °C 9.3 °C, 2020 -0.9 °C, 2014
Day Maximum (09-21) 6.8 °C 11:21 8.2 °C 12.5 °C, 2012 1.5 °C, 2010
Max 10m Temp Rise 0.2 °C 09:55 0.3 °C 0.6 °C, 2014 0.1 °C, 2010
Max 1hr Temp Rise 0.7 °C 10:45 1.1 °C 2.7 °C, 2014 0.3 °C, 2024
Max 1hr Hum Rise 7% 18:20 4% 11%, 2015 2%, 2010
Max 10m Temp Fall 0.8 °C 17:03 0.5 °C 0.8 °C, 2017 0.1 °C, 2010
Max 1hr Temp Fall 3.1 °C 17:31 1.5 °C 3.1 °C, 2017 0.3 °C, 2010
Max 1hr Hum Fall 4% 21:18 6% 16%, 2013 2%, 2011
Max 10m Wind Speed 12.7 mph 21:53 8.9 mph 16.7 mph, 2023 3.0 mph, 2022
Minimum Feels-like -4.9 °C 20:43 -0.9 °C 3.9 °C, 2019 -4.9 °C, 2017
Maximum Feels-like 6.6 °C 12:52 7.8 °C 14.0 °C, 2011 1.4 °C, 2010
Mean Feels-like 1.7 °C 3.7 °C 10.6 °C, 2023 -1.8 °C, 2010
Air-frost Hrs 0 hrs 2 hrs 9 hrs, 2014 0 hrs, 2010
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.9 °C (+1.1) 5.4 °C (+0.7) 10.2 °C (+5.4), 2014 1.1 °C (-3.7), 2010
Humidity Range 25% 14% 43%, 2013 8%, 2024
Pressure Range 22 hPa 8 hPa 22 hPa, 2017 4 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]20 hrs (76%) [23%] 6.5 [89%], 2022 0 [0%], 2009
Wet Hours 10
[Mean rain rate: 1.6 mm/h]		41 hrs (156%) [14%] 10, 2011 , 2009
Cloud Cover Overcast
Events Snowfall: ~4 cm
Comments 11-20 Rain -> Snow (17- Snow); some settling of snow on favoured surfaces
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 12th January 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