Daily Report for 20th January 2015

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature -3.6 °C (-6.5) 05:34 2.9 °C (-0.2) 7.6 °C (+4.7), 2021 -3.6 °C (-6.5), 2015
Maximum Temperature 4.2 °C (-3.6) 20:11 9.0 °C (+1.2) 10.4 °C (+2.6), 2021 -0.3 °C (-8.1), 2013
Mean Temperature 0.6 °C (-5.1) 6.2 °C (+0.5) 9.8 °C, 2021 -1.0 °C, 2013
Minimum Humidity 71% 22:24 69% 87%, 2010 45%, 2017
Maximum Humidity 97% 10:32 92% 98%, 2013 76%, 2017
Mean Humidity 86% 82% 94%, 2014 67%, 2017
Minimum Pressure 1005 hPa 23:58 1010 hPa 1045 hPa, 2020 974 hPa, 2021
Maximum Pressure 1011 hPa 05:45 1020 hPa 1050 hPa, 2020 996 hPa, 2009
Mean Pressure 1009 hPa 1015 hPa 1048 hPa, 2020 988 hPa, 2021
Mean Wind Speed 2.9 mph (-2.3) 6.6 mph (+1.4) 13.7 mph, 2021 0.4 mph, 2014
Maximum Wind Speed 16.1 mph 23:00 17.5 mph 24.7 mph, 2021 4.0 mph, 2016
Maximum Gust 19.9 mph 22:54 25.0 mph 37.6 mph, 2021 4.9 mph, 2016
Mean Wind Direction SSE
Rainfall 0.0 mm 61.5 mm (162%) 8.0 mm, 2013
Maximum Hourly Rain n/a 2.2, 2018
Maximum 10-min Rain n/a 1.2, 2021
Maximum Rain Rate n/a 14.4, 2021
Minimum Dew Point -4.6 °C 05:36 -0.2 °C 5.7 °C, 2021 -5.4 °C, 2016
Maximum Dew Point 1.1 °C 12:12 7.0 °C 8.9 °C, 2021 -1.9 °C, 2017
Mean Dew Point -1.6 °C 3.2 °C 8.2 °C, 2021 -3.3 °C, 2017
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) -3.6 °C 05:34 4.5 °C 9.8 °C, 2021 -3.6 °C, 2015
Day Maximum (09-21) 4.2 °C 20:11 8.2 °C 10.3 °C, 2021 -0.3 °C, 2013
Max 10m Temp Rise 0.4 °C 11:55 0.3 °C 0.7 °C, 2014 0.1 °C, 2010
Max 1hr Temp Rise 1.9 °C 11:55 1.0 °C 2.6 °C, 2014 0.1 °C, 2010
Max 1hr Hum Rise 3% 18:15 6% 9%, 2024 1%, 2010
Max 10m Temp Fall 0.2 °C 02:05 0.4 °C 0.8 °C, 2021 0.1 °C, 2010
Max 1hr Temp Fall 0.7 °C 01:40 1.1 °C 1.8 °C, 2014 0.3 °C, 2010
Max 1hr Hum Fall 7% 12:46 9% 10%, 2017 2%, 2013
Max 10m Wind Speed 10.8 mph 23:09 12.6 mph 17.8 mph, 2021 3.0 mph, 2016
Minimum Feels-like -6.1 °C 08:10 -1.0 °C 2.9 °C, 2021 -8.4 °C, 2013
Maximum Feels-like 3.8 °C 15:12 9.3 °C 11.1 °C, 2021 -0.5 °C, 2013
Mean Feels-like -0.8 °C 4.3 °C 8.0 °C, 2021 -4.4 °C, 2013
Air-frost Hrs 11 hrs 1 hrs 24 hrs, 2013 0 hrs, 2010
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 7.8 °C (+2.9) 6.1 °C (+1.4) 7.8 °C (+2.9), 2015 1.4 °C (-3.5), 2010
Humidity Range 26% 24% 31%, 2017 8%, 2010
Pressure Range 6 hPa 10 hPa 23 hPa, 2021 3 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 4 [52%]47 hrs (108%) [32%] 7.7 [101%], 2017 0 [0%], 2010
Wet Hours 0.256 hrs (129%) [12%] 13, 2013 , 2009
Cloud Cover Mostly Sunny with periods of Partly Cloudy
Events Air Frost
Comments some eve Slight Showers
Extra Comments
Issues None known
Observer Absent? No
Pond Temperature (Heath) 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 20th January 2015.
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