Daily Report for 25th July 2021

Measure	Value (anomaly)	Time	Month cumul.	Record High	Record Low
Minimum Temperature	16.7 °C (+2.0)	05:52	14.7 °C (+0.6)	19.4 °C (+4.7), 2019	10.4 °C (-4.3), 2011
Maximum Temperature	21.2 °C (-2.1)	13:50	23.8 °C (+0.8)	36.8 °C (+13.5), 2019	20.2 °C (-3.1), 2023
Mean Temperature	17.9 °C (-0.1)		19.1 °C (+0.7)	28.4 °C, 2019	15.5 °C, 2015
Minimum Humidity	79%	13:59	61%	83%, 2024	32%, 2012
Maximum Humidity	95%	22:48	91%	95%, 2009	70%, 2011
Mean Humidity	90%		78%	90%, 2021	50%, 2012
Minimum Pressure	1008 hPa	04:47	1015 hPa	1019 hPa, 2025	1004 hPa, 2015
Maximum Pressure	1011 hPa	22:54	1020 hPa	1023 hPa, 2009	1011 hPa, 2021
Mean Pressure	1009 hPa		1017 hPa	1020 hPa, 2025	1009 hPa, 2020
Mean Wind Speed	2.4 mph (-1.9)		2.7 mph (-1.6)	6.8 mph, 2022	2.3 mph, 2018
Maximum Wind Speed	8.1 mph	13:49	10.4 mph	18.7 mph, 2020	8.1 mph, 2021
Maximum Gust	14.8 mph	15:30	15.5 mph	27.4 mph, 2016	10.7 mph, 2011
Mean Wind Direction	n/a		SSE	N, 2011	NNE, 2012
Rainfall	38.4 mm		105.1 mm (283%)	38.4 mm, 2021	0.0 mm, 2009
Maximum Hourly Rain	25.5 mm	17:17	2.3 mm	25.5 mm, 2021	1.0 mm, 2024
Maximum 10-min Rain	10.4 mm	16:43	0.8 mm	10.4 mm, 2021	0.3 mm, 2024
Maximum Rain Rate	102 mm/h	16:43	10 mm/h	102 mm/h, 2014	1.4 mm/h, 2024
Minimum Dew Point	15.1 °C	03:04	12.5 °C	15.1 °C, 2021	4.3 °C, 2011
Maximum Dew Point	17.8 °C	13:46	17.1 °C	21.1 °C, 2019	11.0 °C, 2011
Mean Dew Point	16.2 °C		14.8 °C	17.4 °C, 2019	7.5 °C, 2011
Measure	Value	Time	Month cumul.	Record High	Record Low
Night Minimum (21-09)	16.7 °C	06:00	14.8 °C	19.4 °C, 2019	10.4 °C, 2011
Day Maximum (09-21)	21.2 °C	13:51	23.8 °C	36.8 °C, 2019	20.2 °C, 2023
Max 10m Temp Rise	0.4 °C	11:04	0.6 °C	1.1 °C, 2012	0.3 °C, 2024
Max 1hr Temp Rise	1.4 °C	11:14	2.2 °C	4.7 °C, 2012	1.3 °C, 2024
Max 1hr Hum Rise	10%	14:56	10%	28%, 2014	4%, 2025
Max 10m Temp Fall	0.8 °C	16:47	0.6 °C	2.6 °C, 2014	0.4 °C, 2010
Max 1hr Temp Fall	1.9 °C	14:49	2.2 °C	5.6 °C, 2014	1.2 °C, 2010
Max 1hr Hum Fall	5%	11:22	9%	20%, 2015	5%, 2021
Max 10m Wind Speed	6.1 mph	15:33	7.4 mph	12.7 mph, 2016	3.5 mph, 2009
Minimum Feels-like	20.8 °C	04:59	17.5 °C	23.1 °C, 2019	10.4 °C, 2011
Maximum Feels-like	27.1 °C	13:46	28.9 °C	44.6 °C, 2019	21.8 °C, 2023
Mean Feels-like	22.6 °C		23.0 °C	34.1 °C, 2019	16.1 °C, 2015
Air-frost Hrs	0 hrs		0 hrs	0 hrs, 2009	0 hrs, 2009
Minimum PM2.5	n/a		0.0 µg/m³	5.7 µg/m³, 2026	0.0 µg/m³, 2009
Maximum PM2.5	n/a		0.0 µg/m³	13.5 µg/m³, 2026	13.5 µg/m³, 2026
Mean PM2.5	n/a		0.0 µg/m³	9.1 µg/m³, 2026	9.1 µg/m³, 2026
Measure	Value (anomaly)		Month cumul.	Record High	Record Low
Temperature Range	4.5 °C (-4.1)		9.1 °C	17.4 °C, 2019	4.4 °C, 2024
Humidity Range	16%		31%	52%, 2009	12%, 2024
Pressure Range	3 hPa		5 hPa	13 hPa, 2015	2 hPa, 2013

Observation	Detail
Sun Hours	0 hrs [0%]
Wet Hours	7 hrs
Cloud Cover	Overcast
Events	Moderate Thunderstorm
Comments	T-storm w T rain
Observer Absent?	Yes - observations may be unreliable
Pond Temperature	22.0 °C

Notes: Detailed daily weather report for Hampstead, NW3, London on 25th July 2021. 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.

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Daily Graph of Conditions

Wind direction

Air pollution

Wind rose

Webcam Summary of Cloud Conditions

Full resolution images at up-to 5 minute intervals