Daily Report for 4th January 2015

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Measure Value (anomaly) Time Month cumul. Record High Record Low
Minimum Temperature -1.0 °C (-4.2) 06:33 2.7 °C (-0.5) 10.4 °C (+7.2), 2023 -4.2 °C (-7.4), 2010
Maximum Temperature 4.5 °C (-3.3) 23:58 8.8 °C (+1.0) 13.6 °C (+5.8), 2023 0.6 °C (-7.2), 2009
Mean Temperature 1.9 °C (-3.7) 5.9 °C (+0.2) 12.2 °C, 2023 -2.4 °C, 2010
Minimum Humidity 96% 00:01 75% 96%, 2015 51%, 2009
Maximum Humidity 98% 10:03 95% 98%, 2015 72%, 2009
Mean Humidity 97% 87% 97%, 2015 62%, 2009
Minimum Pressure 1031 hPa 00:46 1021 hPa 1041 hPa, 2019 982 hPa, 2016
Maximum Pressure 1036 hPa 13:30 1034 hPa 1044 hPa, 2019 984 hPa, 2016
Mean Pressure 1034 hPa 1028 hPa 1042 hPa, 2019 982 hPa, 2016
Mean Wind Speed 2.4 mph (-2.8) 5.7 mph (+0.5) 10.4 mph, 2023 1.8 mph, 2019
Maximum Wind Speed 9.0 mph 11:30 15.7 mph 28.6 mph, 2018 6.2 mph, 2010
Maximum Gust 11.4 mph 13:08 22.1 mph 42.6 mph, 2018 8.1 mph, 2010
Mean Wind Direction SW
Rainfall 0.0 mm 17.1 mm (225%) 17.9 mm, 2024
Maximum Hourly Rain n/a 4.6, 2024
Maximum 10-min Rain n/a 1.7, 2022
Maximum Rain Rate n/a 30, 2022
Minimum Dew Point -1.4 °C 06:33 0.2 °C 8.1 °C, 2023 -5.4 °C, 2010
Maximum Dew Point 3.9 °C 23:43 7.8 °C 11.7 °C, 2023 -1.1 °C, 2010
Mean Dew Point 1.5 °C 3.6 °C 10.0 °C, 2023 -4.0 °C, 2010
Measure Value Time Month cumul. Record High Record Low
Night Minimum (21-09) -1.0 °C 06:33 4.2 °C 11.4 °C, 2023 -4.2 °C, 2010
Day Maximum (09-21) * 3.2 °C * 20:57 7.0 °C 13.6 °C, 2023 0.6 °C, 2009
Max 10m Temp Rise 0.4 °C 07:01 0.2 °C 0.7 °C, 2010 0.1 °C, 2013
Max 1hr Temp Rise 1.1 °C 09:34 0.7 °C 2.2 °C, 2010 0.4 °C, 2013
Max 1hr Hum Rise 1% 01:01 4% 7%, 2012 1%, 2015
Max 10m Temp Fall 0.4 °C 03:25 0.3 °C 1.6 °C, 2022 0.1 °C, 2020
Max 1hr Temp Fall 1.1 °C 04:01 1.0 °C 3.9 °C, 2022 0.3 °C, 2020
Max 1hr Hum Fall 1% 01:52 7% 14%, 2018 1%, 2015
Max 10m Wind Speed 6.5 mph 11:33 11.1 mph 20.9 mph, 2018 4.3 mph, 2010
Minimum Feels-like -3.1 °C 06:50 -0.6 °C 10.9 °C, 2023 -7.7 °C, 2010
Maximum Feels-like 4.4 °C 23:42 9.7 °C 15.1 °C, 2023 1.3 °C, 2010
Mean Feels-like 0.6 °C 4.3 °C 13.5 °C, 2023 -3.5 °C, 2010
Air-frost Hrs 4 hrs 0.9 hrs 20 hrs, 2010 0 hrs, 2011
Measure Value (anomaly) Month cumul. Record High Record Low
Temperature Range 5.5 °C (+0.8) 6.1 °C (+1.4) 7.0 °C (+2.3), 2022 2.4 °C (-2.3), 2011
Humidity Range 2% 20% 29%, 2018 2%, 2015
Pressure Range 5 hPa 13 hPa 22 hPa, 2025 2 hPa, 2013
Measure Value [% of max] Month cumul. Record High Record Low
Sun Hours 0 [0%]6 hrs (71%) [21%] 7 [98%], 2010 0 [0%], 2014
Wet Hours 013 hrs (150%) [14%] 8, 2014 , 2009
Cloud Cover Overcast
Events Dense Fog
Air Frost
Comments -09 Dense Fog
Extra Comments Fog rain-tips removed, presumed erroneous
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 4th January 2015.
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