Daily Report for 31st May 2011

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature 7.8 °C (-3.0) 05:25 9.5 °C (+0.4) 16.4 °C (+5.6), 2025 6.8 °C (-4.0), 2014
Maximum Temperature 17.7 °C (-1.6) 17:39 18.5 °C (+0.7) 26.7 °C (+7.4), 2025 13.2 °C (-6.1), 2016
Mean Temperature 12.7 °C (-2.3) 14.2 °C (+0.5) 21.1 °C, 2025 11.9 °C, 2022
Minimum Humidity 35% 18:35 42% 78%, 2024 35%, 2011
Maximum Humidity 87% 05:40 80% 97%, 2018 78%, 2020
Mean Humidity 63% 60% 88%, 2018 55%, 2020
Minimum Pressure 1012 hPa 01:13 1015 hPa 1026 hPa, 2023 1004 hPa, 2015
Maximum Pressure 1027 hPa 23:21 1020 hPa 1030 hPa, 2023 1012 hPa, 2015
Mean Pressure 1020 hPa 1018 hPa 1028 hPa, 2023 1007 hPa, 2015
Mean Wind Speed 4.1 mph (-0.6) 6.0 mph (+1.3) 7.2 mph, 2016 1.0 mph, 2014
Maximum Wind Speed 11.8 mph 14.8 mph 17.0 mph, 2015 6.4 mph, 2014
Maximum Gust 16.8 mph 12:25 21.3 mph 26.5 mph, 2020 8.7 mph, 2014
Mean Wind Direction NW
Rainfall trace 24.1 mm (52%) 12.4, 2016
Maximum Hourly Rain n/a 5.8, 2016
Maximum 10-min Rain n/a 1.3, 2016
Maximum Rain Rate n/a 24, 2016
Minimum Dew Point 1.7 °C 21:45 3.1 °C 14.2 °C, 2018 0.2 °C, 2015
Maximum Dew Point 8.8 °C 00:06 9.2 °C 18.2 °C, 2018 8.8 °C, 2011
Mean Dew Point 5.1 °C 6.1 °C 15.9 °C, 2018 5.1 °C, 2011
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) 7.8 °C 05:25 9.7 °C 16.4 °C, 2025 6.8 °C, 2014
Day Maximum (09-21) 17.7 °C 17:35 18.5 °C 26.7 °C, 2025 12.9 °C, 2016
Max 10m Temp Rise 0.6 °C 14:44 0.7 °C 1.0 °C, 2021 0.3 °C, 2016
Max 1hr Temp Rise 2.1 °C 08:41 2.7 °C 4.4 °C, 2021 0.8 °C, 2016
Max 1hr Hum Rise 9% 23:00 8% 17%, 2022 4%, 2018
Max 10m Temp Fall 0.3 °C 12:43 0.4 °C 1.6 °C, 2022 0.2 °C, 2016
Max 1hr Temp Fall 1.1 °C 22:24 1.6 °C 3.1 °C, 2022 0.6 °C, 2016
Max 1hr Hum Fall 9% 15:28 10% 18%, 2014 2%, 2016
Max 10m Wind Speed 8.2 mph 13:15 10.2 mph 12.8 mph, 2015 3.9 mph, 2014
Minimum Feels-like 5.6 °C 04:56 8.7 °C 19.2 °C, 2025 5.6 °C, 2011
Maximum Feels-like 17.7 °C 17:37 19.0 °C 30.3 °C, 2025 14.7 °C, 2016
Mean Feels-like 12.4 °C 14.5 °C 24.4 °C, 2025 12.4 °C, 2011
Air-frost Hrs 0 hrs 0 hrs 0 hrs, 2009 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 9.9 °C (+1.4) 9.0 °C (+0.3) 15.3 °C (+6.8), 2021 2.3 °C (-6.2), 2016
Humidity Range 52% 38% 52%, 2011 13%, 2024
Pressure Range 15 hPa 6 hPa 15 hPa, 2011 2 hPa, 2009
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 9 [61%]218 hrs (115%) [50%] 14.8 [100%], 2020 0 [0%], 2016
Wet Hours 0.313 hrs (32%) [1.7%] 7, 2015 0, 2009
Cloud Cover am: Sunny transitioned to Mostly Cloudy
pm: Partly Cloudy
Events None
Comments 1230, 14 Moderate Showers
Extra Comments
Issues None known
Observer Absent? Yes - observations may be unreliable
Pond Temperature @ Hampstead Heath 0.0 °C
Notes
Detailed daily weather report for Hampstead nw3 in London on 31st May 2011.
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.
View monthly summary

Daily Graph of Conditions

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Webcam Summary of Cloud Conditions

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Wind rose