Daily Report for 4th April 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 2.1 °C (-3.4) 03:43 4.4 °C (-1.0) 11.1 °C (+5.6), 2014 -0.2 °C (-5.7), 2023
Maximum Temperature 15.2 °C (+1.9) 17:38 12.0 °C (-1.2) 17.3 °C (+4.1), 2009 2.7 °C (-10.6), 2013
Mean Temperature 8.8 °C (-0.7) 8.1 °C (-1.1) 12.9 °C, 2014 1.6 °C, 2013
Minimum Humidity 47% 16:36 59% 71%, 2015 38%, 2009
Maximum Humidity 86% 04:14 85% 95%, 2015 80%, 2017
Mean Humidity 68% 72% 85%, 2024 67%, 2020
Minimum Pressure 1018 hPa 23:47 1025 hPa 1026 hPa, 2023 993 hPa, 2018
Maximum Pressure 1033 hPa 00:03 1033 hPa 1033 hPa, 2021 1000 hPa, 2019
Mean Pressure 1026 hPa 1029 hPa 1028 hPa, 2023 995 hPa, 2018
Mean Wind Speed 3.1 mph (-1.8) 6.1 mph (+1.2) 9.4 mph, 2013 2.4 mph, 2009
Maximum Wind Speed 11.1 mph 16:43 13.5 mph 20.9 mph, 2018 8.2 mph, 2017
Maximum Gust 16.0 mph 12:43 19.7 mph 35.6 mph, 2018 12.6 mph, 2017
Mean Wind Direction WNW
Rainfall 0.0 mm 0.0 mm (0%) 3.8 mm, 2022
Maximum Hourly Rain n/a 1.5, 2022
Maximum 10-min Rain n/a 0.7, 2022
Maximum Rain Rate n/a 7.2, 2022
Minimum Dew Point -0.5 °C 03:07 0.6 °C 7.8 °C, 2024 -6.7 °C, 2013
Maximum Dew Point 5.7 °C 23:25 5.5 °C 12.2 °C, 2024 0.9 °C, 2013
Mean Dew Point 2.9 °C 3.2 °C 10.0 °C, 2024 -3.2 °C, 2013
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 2.1 °C 03:43 4.9 °C 11.5 °C, 2014 -0.2 °C, 2023
Day Maximum (09-21) 15.2 °C 17:38 12.0 °C 17.3 °C, 2009 2.7 °C, 2013
Max 10m Temp Rise 0.7 °C 10:46 0.6 °C 1.3 °C, 2020 0.3 °C, 2014
Max 1hr Temp Rise 2.3 °C 11:30 1.5 °C 4.0 °C, 2020 0.5 °C, 2015
Max 1hr Hum Rise 8% 21:49 6% 15%, 2019 3%, 2015
Max 10m Temp Fall 0.3 °C 01:08 0.5 °C 0.9 °C, 2019 0.3 °C, 2015
Max 1hr Temp Fall 1.5 °C 01:17 1.9 °C 2.6 °C, 2023 0.7 °C, 2013
Max 1hr Hum Fall 8% 13:46 7% 16%, 2013 4%, 2017
Max 10m Wind Speed 7.3 mph 16:19 10.3 mph 15.2 mph, 2018 6.1 mph, 2017
Minimum Feels-like 2.1 °C 03:23 0.9 °C 11.1 °C, 2014 -5.3 °C, 2013
Maximum Feels-like 15.2 °C 17:33 11.3 °C 18.1 °C, 2024 0.1 °C, 2013
Mean Feels-like 8.5 °C 6.1 °C 13.9 °C, 2024 -3.1 °C, 2013
Air-frost Hrs 0 hrs 0 hrs 0.9 hrs, 2023 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 13.1 °C (+5.3) 7.6 °C (-0.1) 14.2 °C (+6.4), 2020 2.6 °C (-5.2), 2013
Humidity Range 39% 26% 57%, 2020 13%, 2017
Pressure Range 15 hPa 7 hPa 21 hPa, 2010 3 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 9 [76%]18 hrs (87%) [37%] 11.8 [100%], 2023 0 [0%], 2013
Wet Hours 00 hrs (0%) [0%] 7, 2022 0, 2011
Cloud Cover am: Overcast transitioned to Sunny
pm: Sunny
Events None
Comments -
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 10.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 4th April 2021.
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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