Daily Report for 20th April 2012

Measure	Value (anomaly)	Time	Month cumul.	Record High	Record Low
Minimum Temperature	5.1 °C (-1.1)	06:26	3.8 °C (-1.9)	13.9 °C (+7.7), 2018	1.4 °C (-4.8), 2013
Maximum Temperature	13.0 °C (-1.8)	11:14	12.2 °C (-1.8)	25.9 °C (+11.1), 2018	10.6 °C (-4.2), 2024
Mean Temperature	8.3 °C (-1.4)		8.0 °C (-1.9)	20.0 °C, 2018	7.2 °C, 2024
Minimum Humidity	54%	12:11	49%	75%, 2014	33%, 2011
Maximum Humidity	94%	07:03	89%	95%, 2014	72%, 2017
Mean Humidity	80%		70%	90%, 2014	54%, 2011
Minimum Pressure	990 hPa	00:48	1001 hPa	1032 hPa, 2017	990 hPa, 2012
Maximum Pressure	995 hPa	18:51	1010 hPa	1037 hPa, 2017	995 hPa, 2012
Mean Pressure	992 hPa		1006 hPa	1035 hPa, 2017	992 hPa, 2012
Mean Wind Speed	4.6 mph (-0.3)		4.7 mph (-0.2)	7.9 mph, 2020	1.0 mph, 2021
Maximum Wind Speed	15.6 mph		13.5 mph	18.4 mph, 2020	8.9 mph, 2021
Maximum Gust	25.6 mph	17:38	19.1 mph	28.8 mph, 2023	11.4 mph, 2021
Mean Wind Direction	n/a		SSW	NW, 2018	NE, 2024
Rainfall	8.0 mm		44.5 mm (159%)	8.0 mm, 2012	0.0 mm, 2009
Maximum Hourly Rain	4.9 mm	14:37	1.0 mm	4.9 mm, 2012	1.4 mm, 2023
Maximum 10-min Rain	2.6 mm	13:45	0.6 mm	2.6 mm, 2012	0.5 mm, 2023
Maximum Rain Rate	30 mm/h	13:46	6 mm/h	30 mm/h, 2012	2.9 mm/h, 2023
Minimum Dew Point	3.0 °C	17:47	-0.7 °C	9.6 °C, 2018	-3.0 °C, 2010
Maximum Dew Point	7.2 °C	09:47	5.9 °C	14.1 °C, 2018	4.2 °C, 2013
Mean Dew Point	4.9 °C		2.5 °C	11.5 °C, 2018	-0.1 °C, 2013
Measure	Value	Time	Month cumul.	Record High	Record Low
Night Minimum (21-09)	5.1 °C	06:25	4.1 °C	13.9 °C, 2018	1.4 °C, 2013
Day Maximum (09-21)	13.0 °C	11:13	12.2 °C	25.9 °C, 2018	10.6 °C, 2024
Max 10m Temp Rise	0.8 °C	08:13	0.7 °C	1.0 °C, 2013	0.4 °C, 2014
Max 1hr Temp Rise	2.7 °C	08:57	2.7 °C	4.2 °C, 2013	1.6 °C, 2014
Max 1hr Hum Rise	19%	18:40	12%	29%, 2023	4%, 2010
Max 10m Temp Fall	1.7 °C	17:49	0.8 °C	1.7 °C, 2012	0.4 °C, 2014
Max 1hr Temp Fall	3.6 °C	13:50	2.2 °C	4.3 °C, 2023	1.3 °C, 2017
Max 1hr Hum Fall	13%	11:26	14%	19%, 2013	1%, 2017
Max 10m Wind Speed	9.3 mph	17:49	9.1 mph	14.5 mph, 2023	5.7 mph, 2021
Minimum Feels-like	2.5 °C	06:44	1.3 °C	15.1 °C, 2018	-0.6 °C, 2024
Maximum Feels-like	13.0 °C	11:07	12.2 °C	28.6 °C, 2018	10.6 °C, 2024
Mean Feels-like	7.2 °C		6.9 °C	22.0 °C, 2018	5.4 °C, 2024
Air-frost Hrs	0 hrs		0.3 hrs	0 hrs, 2009	0 hrs, 2009
Minimum PM2.5	n/a		0.0 µg/m³	0.0 µg/m³, 2009	0.0 µg/m³, 2009
Maximum PM2.5	n/a		0.0 µg/m³	n/a	n/a
Mean PM2.5	n/a		0.0 µg/m³	n/a	n/a
Measure	Value (anomaly)		Month cumul.	Record High	Record Low
Temperature Range	7.9 °C (-0.7)		8.3 °C	15.3 °C, 2011	6.7 °C, 2014
Humidity Range	40%		40%	56%, 2013	20%, 2014
Pressure Range	5 hPa		9 hPa	11 hPa, 2014	2 hPa, 2011

Observation	Detail
Sun Hours	5 hrs [39%]
Wet Hours	2 hrs
Cloud Cover	am: Mostly Sunny with periods of Partly Cloudy pm: Mostly Cloudy with periods of Overcast
Events	Hail (small stones), Light Thunderstorm
Comments	13 L Hail (S); 1330 T-storm (L); 14? 18 H Shs
Observer Absent?	No
Pond Temperature	0.0 °C

Notes: Detailed daily weather report for Hampstead, NW3, London on 20th April 2012. Times of extremes use the midpoint of the longest continuous period at that value. Cumulative anomalies are relative to the expected value for the month-to-date. Sun and wet hours are derived from webcam/rainfall analysis and may be adjusted. Data should be viewed with appropriate caution.

View monthly summary

Daily Report for 20th April 2012

Daily Graph of Conditions

Wind direction

Air pollution

Wind rose

Webcam Summary of Cloud Conditions