Daily Report for 18th April 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 6.7 °C (+0.7) 06:13 8.0 °C (+2.3) 12.3 °C (+6.3), 2018 0.4 °C (-5.6), 2021
Maximum Temperature 18.1 °C (+3.6) 13:54 17.2 °C (+3.4) 24.9 °C (+10.4), 2018 10.8 °C (-3.7), 2023
Mean Temperature 12.6 °C (+2.1) 12.6 °C (+2.8) 18.3 °C, 2018 8.2 °C, 2012
Minimum Humidity 33% 15:40 46% 70%, 2020 28%, 2018
Maximum Humidity 86% 07:30 80% 97%, 2009 70%, 2013
Mean Humidity 59% 63% 81%, 2012 54%, 2017
Minimum Pressure 1013 hPa 22:08 1020 hPa 1027 hPa, 2023 977 hPa, 2012
Maximum Pressure 1024 hPa 00:08 1024 hPa 1032 hPa, 2017 992 hPa, 2012
Mean Pressure 1018 hPa 1022 hPa 1029 hPa, 2017 984 hPa, 2012
Mean Wind Speed 4.6 mph (-0.3) 4.8 mph (-0.1) 10.6 mph, 2013 0.9 mph, 2021
Maximum Wind Speed 13.5 mph 12.7 mph 20.8 mph, 2013 7.1 mph, 2010
Maximum Gust 19.9 mph 12:18 18.1 mph 30.1 mph, 2013 10.0 mph, 2010
Mean Wind Direction ENE
Rainfall 0.0 mm 1.7 mm (7%) 3.4 mm, 2012
Maximum Hourly Rain n/a 1.3, 2020
Maximum 10-min Rain n/a 0.6, 2012
Maximum Rain Rate n/a 5, 2012
Minimum Dew Point 1.0 °C 19:59 2.3 °C 5.0 °C, 2018 -3.2 °C, 2021
Maximum Dew Point 9.1 °C 10:23 8.3 °C 13.4 °C, 2018 1.3 °C, 2017
Mean Dew Point 3.9 °C 5.3 °C 10.4 °C, 2018 -0.8 °C, 2017
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 6.7 °C 06:10 8.2 °C 12.3 °C, 2018 0.4 °C, 2021
Day Maximum (09-21) 18.1 °C 13:55 17.2 °C 24.9 °C, 2018 10.8 °C, 2023
Max 10m Temp Rise 0.7 °C 09:39 0.5 °C 1.2 °C, 2009 0.4 °C, 2020
Max 1hr Temp Rise 3.4 °C 10:22 2.3 °C 4.7 °C, 2021 1.5 °C, 2020
Max 1hr Hum Rise 5% 01:03 7% 24%, 2013 4%, 2016
Max 10m Temp Fall 0.7 °C 18:16 0.4 °C 2.5 °C, 2013 0.3 °C, 2023
Max 1hr Temp Fall 3.0 °C 19:39 1.8 °C 4.3 °C, 2013 1.0 °C, 2023
Max 1hr Hum Fall 12% 12:20 11% 19%, 2021 6%, 2020
Max 10m Wind Speed 9.3 mph 16:58 8.7 mph 14.9 mph, 2013 4.7 mph, 2021
Minimum Feels-like 5.1 °C 06:55 6.8 °C 13.4 °C, 2018 -0.3 °C, 2024
Maximum Feels-like 18.1 °C 13:49 17.7 °C 26.6 °C, 2018 10.8 °C, 2023
Mean Feels-like 12.5 °C 12.6 °C 19.8 °C, 2018 6.3 °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 11.4 °C (+3.0) 9.2 °C (+1.0) 16.0 °C (+7.6), 2010 4.1 °C (-4.3), 2023
Humidity Range 53% 34% 56%, 2018 19%, 2023
Pressure Range 11 hPa 4 hPa 15 hPa, 2012 2 hPa, 2022
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 7 [55%]103 hrs (109%) [47%] 12.7 [100%], 2018 0.5 [4%], 2020
Wet Hours 03.5 hrs (13%) [0.8%] 4, 2012 0, 2009
Cloud Cover am: Mostly Cloudy transitioned to Partly Cloudy
pm: Partly Cloudy with periods of Sunny
Events None
Comments -
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 18th April 2011.
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

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Webcam Summary of Cloud Conditions

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Wind rose