Daily Report for 30th April 2012

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 8.9 °C (+1.8) 06:22 4.8 °C (-1.4) 10.9 °C (+3.8), 2011 1.8 °C (-5.3), 2021
Maximum Temperature 18.0 °C (+1.9) 14:38 12.7 °C (-1.9) 20.4 °C (+4.3), 2014 8.7 °C (-7.4), 2018
Mean Temperature 13.7 °C (+1.9) 8.5 °C (-1.6) 15.1 °C, 2011 6.4 °C, 2018
Minimum Humidity 40% 13:11 51% 62%, 2018 36%, 2013
Maximum Humidity 82% 23:58 90% 97%, 2014 71%, 2017
Mean Humidity 61% 73% 83%, 2020 52%, 2017
Minimum Pressure 1007 hPa 00:43 1000 hPa 1027 hPa, 2022 993 hPa, 2020
Maximum Pressure 1016 hPa 19:50 1009 hPa 1033 hPa, 2022 998 hPa, 2020
Mean Pressure 1012 hPa 1004 hPa 1030 hPa, 2022 996 hPa, 2020
Mean Wind Speed 7.5 mph (+2.6) 5.5 mph (+0.6) 7.9 mph, 2018 0.9 mph, 2022
Maximum Wind Speed 17.3 mph 15.2 mph 18.1 mph, 2011 7.0 mph, 2022
Maximum Gust 21.9 mph 10:08 21.9 mph 30.0 mph, 2020 11.5 mph, 2019
Mean Wind Direction ESE
Rainfall trace 100.4 mm (239%) 10.9, 2020
Maximum Hourly Rain n/a 4.6, 2020
Maximum 10-min Rain n/a 1.5, 2020
Maximum Rain Rate n/a 30, 2010
Minimum Dew Point 3.6 °C 12:28 0.5 °C 5.9 °C, 2010 -3.1 °C, 2016
Maximum Dew Point 9.5 °C 23:58 6.7 °C 12.5 °C, 2014 2.9 °C, 2013
Mean Dew Point 5.9 °C 3.5 °C 8.7 °C, 2024 -0.9 °C, 2016
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 8.9 °C 06:22 5.0 °C 10.9 °C, 2011 1.8 °C, 2021
Day Maximum (09-21) 18.0 °C 14:37 12.6 °C 20.4 °C, 2014 8.7 °C, 2018
Max 10m Temp Rise 0.6 °C 07:07 0.7 °C 0.9 °C, 2021 0.4 °C, 2011
Max 1hr Temp Rise 2.6 °C 07:39 2.5 °C 4.0 °C, 2024 0.9 °C, 2018
Max 1hr Hum Rise 10% 20:26 11% 21%, 2021 5%, 2009
Max 10m Temp Fall 0.5 °C 13:33 0.8 °C 1.2 °C, 2020 0.3 °C, 2018
Max 1hr Temp Fall 1.4 °C 20:16 2.1 °C 4.1 °C, 2020 0.9 °C, 2018
Max 1hr Hum Fall 11% 10:27 14% 20%, 2014 6%, 2017
Max 10m Wind Speed 10.9 mph 13:23 10.0 mph 14.1 mph, 2020 5.2 mph, 2022
Minimum Feels-like 6.1 °C 06:24 1.8 °C 11.3 °C, 2011 -1.2 °C, 2018
Maximum Feels-like 18.0 °C 13:19 12.7 °C 20.9 °C, 2024 8.0 °C, 2018
Mean Feels-like 13.6 °C 7.4 °C 15.4 °C, 2011 2.8 °C, 2018
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 9.1 °C (+0.1) 7.9 °C (-0.6) 14.5 °C (+5.5), 2022 4.0 °C (-5.0), 2018
Humidity Range 42% 39% 60%, 2014 24%, 2009
Pressure Range 9 hPa 9 hPa 13 hPa, 2016 2 hPa, 2021
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 10 [75%]118 hrs (73%) [31%] 13.4 [100%], 2011 0 [0%], 2018
Wet Hours 1104 hrs (227%) [14%] 12, 2018 0, 2011
Cloud Cover am: Sunny or Mostly Sunny
pm: Mostly Sunny transitioned to Hazy
Events None
Comments 21, 23 Light/Moderate 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 30th 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