Daily Report for 17th March 2018

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature -1.7 °C (-6.1) 20:47 3.4 °C (-0.5) 10.7 °C (+6.3), 2023 -1.7 °C (-6.1), 2018
Maximum Temperature 7.1 °C (-3.8) 00:02 9.1 °C (-1.3) 15.4 °C (+4.5), 2009 7.1 °C (-3.8), 2018
Mean Temperature 0.5 °C (-5.0) 6.0 °C (-0.9) 12.1 °C, 2024 0.5 °C, 2018
Minimum Humidity 78% 13:53 70% 79%, 2024 43%, 2016
Maximum Humidity 93% 02:51 93% 98%, 2011 78%, 2017
Mean Humidity 87% 84% 90%, 2024 65%, 2010
Minimum Pressure 1006 hPa 00:24 992 hPa 1032 hPa, 2021 987 hPa, 2013
Maximum Pressure 1008 hPa 10:41 1000 hPa 1040 hPa, 2022 993 hPa, 2013
Mean Pressure 1007 hPa 996 hPa 1034 hPa, 2009 990 hPa, 2013
Mean Wind Speed 10.9 mph (+5.7) 6.4 mph (+1.2) 10.9 mph, 2018 1.9 mph, 2009
Maximum Wind Speed 21.2 mph 14:47 15.5 mph 21.2 mph, 2018 7.8 mph, 2011
Maximum Gust 32.3 mph 13:20 23.9 mph 32.3 mph, 2018 10.7 mph, 2011
Mean Wind Direction NE
Rainfall / Snow-melt approx. 4.4 mm 35.9 mm (168%) 5.3 mm, 2023
Maximum Hourly Rain n/a 2.6, 2012
Maximum 10-min Rain n/a 1.5, 2012
Maximum Rain Rate n/a 15, 2012
Minimum Dew Point -4.1 °C 15:15 1.0 °C 9.1 °C, 2023 -4.1 °C, 2018
Maximum Dew Point 5.6 °C 00:02 5.9 °C 12.2 °C, 2024 5.0 °C, 2013
Mean Dew Point -1.5 °C 3.5 °C 10.4 °C, 2024 -1.5 °C, 2018
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) * -0.3 °C * 08:55 3.8 °C 11.2 °C, 2023 -0.3 °C, 2018
Day Maximum (09-21) * 0.1 °C * 12:29 8.6 °C 15.4 °C, 2009 0.1 °C, 2018
Max 10m Temp Rise 0.1 °C 04:23 0.4 °C 1.2 °C, 2009 0.1 °C, 2018
Max 1hr Temp Rise 0.4 °C 10:22 1.4 °C 3.1 °C, 2009 0.4 °C, 2018
Max 1hr Hum Rise 5% 08:17 8% 28%, 2019 3%, 2020
Max 10m Temp Fall 0.5 °C 01:10 0.4 °C 2.3 °C, 2019 0.3 °C, 2015
Max 1hr Temp Fall 1.6 °C 01:36 1.3 °C 4.2 °C, 2019 0.9 °C, 2020
Max 1hr Hum Fall 8% 10:25 9% 22%, 2016 4%, 2012
Max 10m Wind Speed 16.7 mph 12:56 12.1 mph 16.7 mph, 2018 5.2 mph, 2011
Minimum Feels-like -9.2 °C 17:59 -0.9 °C 11.7 °C, 2023 -9.2 °C, 2018
Maximum Feels-like 4.0 °C 00:05 8.3 °C 17.0 °C, 2024 4.0 °C, 2018
Mean Feels-like -5.5 °C 3.5 °C 13.5 °C, 2024 -5.5 °C, 2018
Air-frost Hrs 15 hrs 4 hrs 15 hrs, 2018 0 hrs, 2009
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 8.8 °C (+2.3) 5.7 °C (-0.7) 10.4 °C (+3.9), 2022 3.3 °C (-3.2), 2023
Humidity Range 15% 23% 49%, 2016 13%, 2012
Pressure Range 2 hPa 8 hPa 18 hPa, 2019 2 hPa, 2018
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]26 hrs (43%) [15%] 10 [93%], 2022 0 [0%], 2012
Wet Hours 12
[Mean rain rate: 0.4 mm/h]
55 hrs (191%) [14%] 12, 2018 , 2009
Cloud Cover Overcast
Events Snowfall: ~4 cm
Lying Snow (at 09z): trace amount
Air Frost
Comments o.night Rain -> Snow, continued prolonged Snow spells throughout
Extra Comments amount highly uncertain
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 17th March 2018.
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

day graph

Webcam Summary of Cloud Conditions

daycamsumLarge resolution version

Wind rose