Daily Report for 21st April 2019

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 6.6 °C (+0.4) 06:16 4.5 °C (-1.3) 11.6 °C (+5.4), 2011 0.2 °C (-6.0), 2013
Maximum Temperature 22.8 °C (+8.0) 13:58 13.7 °C (-0.3) 24.4 °C (+9.6), 2011 11.1 °C (-3.7), 2024
Mean Temperature 15.9 °C (+4.2) 9.1 °C (-0.8) 17.5 °C, 2011 7.6 °C, 2024
Minimum Humidity 29% 19:31 53% 68%, 2023 29%, 2019
Maximum Humidity 84% 06:41 88% 98%, 2014 66%, 2011
Mean Humidity 52% 73% 85%, 2023 48%, 2011
Minimum Pressure 1015 hPa 23:59 1014 hPa 1032 hPa, 2015 994 hPa, 2012
Maximum Pressure 1028 hPa 21:22 1020 hPa 1034 hPa, 2015 1002 hPa, 2012
Mean Pressure 1021 hPa 1017 hPa 1033 hPa, 2015 998 hPa, 2012
Mean Wind Speed 3.4 mph (-1.5) 4.4 mph (-0.5) 7.9 mph, 2020 1.9 mph, 2009
Maximum Wind Speed 10.0 mph 13:51 12.8 mph 18.0 mph, 2020 9.4 mph, 2010
Maximum Gust 20.0 mph 16:28 19.2 mph 30.0 mph, 2020 12.7 mph, 2018
Mean Wind Direction E
Rainfall 0.0 mm 10.8 mm (37%) 4.4 mm, 2014
Maximum Hourly Rain n/a 2.2, 2014
Maximum 10-min Rain n/a 0.9, 2014
Maximum Rain Rate n/a 10.8, 2014
Minimum Dew Point -0.1 °C 19:42 1.5 °C 8.7 °C, 2018 -3.7 °C, 2010
Maximum Dew Point 9.5 °C 12:05 6.6 °C 14.1 °C, 2018 0.7 °C, 2010
Mean Dew Point 5.0 °C 4.1 °C 11.2 °C, 2018 -1.6 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 6.6 °C 06:17 4.6 °C 11.6 °C, 2011 0.2 °C, 2013
Day Maximum (09-21) 22.8 °C 14:03 13.7 °C 24.4 °C, 2011 11.1 °C, 2024
Max 10m Temp Rise 1.2 °C 07:22 0.7 °C 1.4 °C, 2013 0.4 °C, 2017
Max 1hr Temp Rise 4.4 °C 07:55 2.5 °C 5.7 °C, 2013 1.3 °C, 2017
Max 1hr Hum Rise 7% 03:09 10% 20%, 2014 4%, 2017
Max 10m Temp Fall 0.3 °C 03:09 0.6 °C 1.0 °C, 2025 0.3 °C, 2019
Max 1hr Temp Fall 1.6 °C 03:09 1.8 °C 2.9 °C, 2014 1.5 °C, 2017
Max 1hr Hum Fall 14% 08:02 11% 25%, 2014 8%, 2010
Max 10m Wind Speed 8.2 mph 16:37 9.7 mph 13.3 mph, 2020 6.9 mph, 2018
Minimum Feels-like 6.3 °C 06:53 1.5 °C 11.7 °C, 2018 -0.9 °C, 2013
Maximum Feels-like 23.0 °C 13:35 13.9 °C 26.2 °C, 2018 11.1 °C, 2024
Mean Feels-like 16.0 °C 8.0 °C 18.8 °C, 2018 5.5 °C, 2024
Air-frost Hrs 0 hrs 0.1 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 16.2 °C (+7.6) 9.2 °C (+1.0) 16.2 °C (+7.6), 2019 5.4 °C (-3.2), 2023
Humidity Range 55% 35% 58%, 2014 24%, 2023
Pressure Range 14 hPa 6 hPa 14 hPa, 2019 2 hPa, 2010
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 13 [101%]129 hrs (117%) [50%] 13 [101%], 2019 0 [0%], 2017
Wet Hours 020 hrs (61%) [3.9%] 4, 2014 0, 2009
Cloud Cover Sunny
Events Maximum possible sunshine
Comments -
Extra Comments
Issues server CPU pegged - some data issues
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath n/a
Notes
Detailed daily weather report for Hampstead nw3 in London on 21st April 2019.
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