Daily Report for 4th May 2021

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 6.0 °C (-1.5) 22:31 4.5 °C (-2.9) 11.8 °C (+4.4), 2015 2.8 °C (-4.7), 2010
Maximum Temperature 13.6 °C (-2.8) 14:46 13.4 °C (-3.0) 20.2 °C (+3.8), 2018 8.9 °C (-7.5), 2012
Mean Temperature 9.7 °C (-2.1) 9.0 °C (-2.9) 15.3 °C, 2018 7.0 °C, 2019
Minimum Humidity 43% 17:34 44% 80%, 2012 33%, 2016
Maximum Humidity 91% 00:00 90% 96%, 2012 73%, 2013
Mean Humidity 70% 70% 89%, 2012 50%, 2016
Minimum Pressure 995 hPa 02:59 1007 hPa 1025 hPa, 2010 992 hPa, 2015
Maximum Pressure 1006 hPa 22:51 1018 hPa 1028 hPa, 2009 1005 hPa, 2015
Mean Pressure 1001 hPa 1013 hPa 1026 hPa, 2010 1001 hPa, 2021
Mean Wind Speed 10.9 mph (+6.2) 6.3 mph (+1.6) 10.9 mph, 2021 2.5 mph, 2018
Maximum Wind Speed 25.2 mph 14:54 17.9 mph 25.2 mph, 2021 8.7 mph, 2012
Maximum Gust 35.4 mph 14:54 26.2 mph 35.4 mph, 2021 10.9 mph, 2014
Mean Wind Direction WNW
Rainfall 1.0 mm 5.6 mm (94%) 4.5 mm, 2015
Maximum Hourly Rain 0.5 mm 06:20 2.6 mm, 2015
Maximum 10-min Rain 0.3 mm 20:17 1.2 mm, 2022
Maximum Rain Rate 0.9 mm/h 06:20 13 mm/h, 2019
Minimum Dew Point 0.5 °C 17:35 0.8 °C 7.5 °C, 2022 -3.9 °C, 2016
Maximum Dew Point 8.5 °C 00:00 6.6 °C 13.3 °C, 2023 3.4 °C, 2010
Mean Dew Point 4.3 °C 3.5 °C 9.8 °C, 2022 1.0 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * 7.9 °C * 07:08 5.0 °C 11.8 °C, 2015 2.8 °C, 2010
Day Maximum (09-21) 13.6 °C 14:46 13.4 °C 20.2 °C, 2018 8.9 °C, 2012
Max 10m Temp Rise 0.8 °C 13:23 0.7 °C 1.0 °C, 2016 0.4 °C, 2010
Max 1hr Temp Rise 1.9 °C 17:05 2.3 °C 4.9 °C, 2016 1.0 °C, 2017
Max 1hr Hum Rise 24% 20:23 17% 24%, 2019 3%, 2012
Max 10m Temp Fall 1.6 °C 15:36 0.9 °C 2.4 °C, 2019 0.2 °C, 2012
Max 1hr Temp Fall 3.3 °C 20:26 2.2 °C 3.7 °C, 2019 0.5 °C, 2012
Max 1hr Hum Fall 19% 17:08 15% 26%, 2013 8%, 2010
Max 10m Wind Speed 17.9 mph 11:53 13.3 mph 17.9 mph, 2021 6.1 mph, 2012
Minimum Feels-like 1.7 °C 21:40 1.5 °C 12.0 °C, 2015 -0.3 °C, 2019
Maximum Feels-like 13.6 °C 14:36 13.4 °C 21.9 °C, 2023 8.9 °C, 2012
Mean Feels-like 7.6 °C 7.9 °C 15.8 °C, 2018 4.6 °C, 2019
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 7.6 °C (-1.4) 8.9 °C (-0.1) 14.4 °C (+5.4), 2016 2.2 °C (-6.8), 2012
Humidity Range 48% 46% 51%, 2015 16%, 2012
Pressure Range 12 hPa 11 hPa 13 hPa, 2015 1 hPa, 2011
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 5 [37%]18 hrs (75%) [32%] 13.5 [100%], 2011 0 [0%], 2012
Wet Hours 2
[Mean rain rate: 0.5 mm/h]
8 hrs (155%) [8.3%] 4, 2015 0, 2010
Cloud Cover am: Mostly Cloudy
pm: Partly Cloudy
Events None
Comments shs
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature (Heath) 12.5 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 4th May 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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