Daily Report for 27th April 2012

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 9.3 °C (+2.5) 23:54 4.6 °C (-1.5) 9.3 °C (+2.5), 2012 0.8 °C (-6.0), 2021
Maximum Temperature 15.0 °C (-0.7) 17:25 12.5 °C (-1.9) 20.8 °C (+5.1), 2010 9.9 °C (-5.8), 2009
Mean Temperature 11.4 °C (+0.9) 8.4 °C (-1.7) 14.1 °C, 2010 6.4 °C, 2016
Minimum Humidity 55% 18:03 49% 78%, 2018 31%, 2021
Maximum Humidity 85% 23:59 89% 95%, 2023 77%, 2017
Mean Humidity 74% 72% 88%, 2024 53%, 2015
Minimum Pressure 1003 hPa 00:13 999 hPa 1027 hPa, 2022 994 hPa, 2009
Maximum Pressure 1015 hPa 22:32 1008 hPa 1031 hPa, 2022 1004 hPa, 2009
Mean Pressure 1009 hPa 1004 hPa 1029 hPa, 2022 999 hPa, 2009
Mean Wind Speed 5.7 mph (+0.8) 5.2 mph (+0.3) 11.5 mph, 2019 1.0 mph, 2021
Maximum Wind Speed 14.0 mph 14.9 mph 22.3 mph, 2019 5.9 mph, 2021
Maximum Gust 23.9 mph 00:17 21.2 mph 34.6 mph, 2019 12.5 mph, 2021
Mean Wind Direction WSW
Rainfall 3.2 mm 72.8 mm (193%) 17.0 mm, 2024
Maximum Hourly Rain 2.3 mm 10:17 3.8 mm, 2024
Maximum 10-min Rain 1.2 mm 09:47 1.2 mm, 2012
Maximum Rain Rate 20 mm/h 09:48 36 mm/h, 2024
Minimum Dew Point 5.3 °C 00:08 0.0 °C 5.3 °C, 2012 -4.2 °C, 2016
Maximum Dew Point 9.5 °C 13:45 6.3 °C 10.6 °C, 2020 1.7 °C, 2016
Mean Dew Point 6.9 °C 3.2 °C 7.5 °C, 2020 -1.6 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 9.5 °C * 06:00 4.7 °C 9.5 °C, 2012 0.8 °C, 2021
Day Maximum (09-21) 15.0 °C 17:24 12.5 °C 20.8 °C, 2010 9.9 °C, 2009
Max 10m Temp Rise 0.7 °C 13:45 0.7 °C 0.8 °C, 2011 0.3 °C, 2022
Max 1hr Temp Rise 2.2 °C 07:56 2.5 °C 2.7 °C, 2017 1.2 °C, 2009
Max 1hr Hum Rise 11% 19:08 12% 19%, 2023 6%, 2010
Max 10m Temp Fall 0.8 °C 09:54 0.8 °C 0.9 °C, 2020 0.3 °C, 2010
Max 1hr Temp Fall 1.9 °C 19:37 2.2 °C 2.7 °C, 2020 0.8 °C, 2018
Max 1hr Hum Fall 11% 17:05 14% 30%, 2015 4%, 2009
Max 10m Wind Speed 10.1 mph 00:02 9.7 mph 18.0 mph, 2019 4.8 mph, 2021
Minimum Feels-like 6.7 °C 06:26 1.8 °C 6.7 °C, 2012 -2.6 °C, 2016
Maximum Feels-like 15.1 °C 17:16 12.5 °C 21.5 °C, 2010 10.7 °C, 2013
Mean Feels-like 11.1 °C 7.3 °C 14.4 °C, 2010 4.5 °C, 2016
Air-frost Hrs 0 hrs 0.2 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.7 °C (-3.3) 7.9 °C (-0.4) 15.7 °C (+6.7), 2021 3.9 °C (-5.1), 2018
Humidity Range 30% 40% 61%, 2021 15%, 2018
Pressure Range 12 hPa 10 hPa 12 hPa, 2012 1 hPa, 2015
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 4 [30%]107 hrs (74%) [32%] 11 [83%], 2011 0 [0%], 2018
Wet Hours 2
[Mean rain rate: 1.6 mm/h]		75 hrs (182%) [12%] 10, 2024 0, 2010
Cloud Cover Partly Cloudy with periods of Mostly Cloudy
Events None
Comments 10-16 occasional Light-Heavy 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 27th April 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

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Webcam Summary of Cloud Conditions

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Wind rose