Humidity Type:
Difference?

Detailed Relative Humidity Data

Current
Measure Value
Relative Humidity 84%
Humidity Trend -4% /hr
24hr Mean Humidity 67%
Wet-Bulb Temperature 17.9 °C
Absolute Humidity 14.33 gm-3
Air Density 1202.17 gm-3
Recent Averages and Extremes
Measure Today Yesterday
Minimum 75%
00:21
45%
17:54
Maximum 90%
07:59
93%
07:30
Mean 84%
67%
Last 6hrs  LondonHumidity31-day chart of mean LondonHumidity 31-day chart of min LondonHumidity 31-day chart of max LondonHumidity
Averages, Extremes and Records
Current Station Lifetime (09-24)
Measure 7-day Month 31-day Year 365-day Overall July 20th Jul
Lowest
Min
45%
19th
44%
4th
38%
29th
38%
29th Jun
38%
29th Jun
20%
9th Jun 2021
20%
Day 19, 2022
31%
2016
Highest
Max
96%
18th
97%
6th
97%
8th
99%
8th Feb
99%
8th Feb
99%
21st Oct 2022
97%
Day 12, 2009
95%
2019
Highest
Min
75%
Today
89%
9th
89%
9th
92%
10th Mar
93%
3rd Dec
98%
23rd Dec 2009
89%
Day 9, 2024
75%
Today
Lowest
Max
90%
Today
82%
1st
81%
29th
81%
28th Jun
81%
29th Jun
56%
20th Jul 2010
56%
Day 20, 2010
56%
2010
Lowest
Mean
67%
19th
64%
4th
60%
29th
60%
29th Jun
60%
29th Jun
39%
2nd May 2013
41%
Day 15, 2013
43%
2010
Highest
Mean
84%
Today
94%
9th
94%
9th
94%
8th Feb
95%
12th Oct
98%
23rd Dec 2009
94%
Day 9, 2024
84%
Today
Averages                
Mean 76% 78% 75% 81% 82% 77% 68% 69%
Mean
Minimum
60% 63% 58% 67% 69% 61% 49% 48%
Mean
Maximum
94% 92% 91% 92% 93% 89% 86% 84%

Past Year Monthly Averages and Extremes (July 2023 - June 2024)
Extremes Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Lowest
Min
37%
7th
41%
23rd
38%
4th
56%
8th
61%
24th
68%
21st
60%
26th
64%
12th
47%
30th
44%
14th
44%
9th
38%
29th
Highest
Max
96%
23rd
98%
9th
98%
15th
98%
18th
99%
13th
98%
3rd
96%
1st
99%
8th
97%
4th
95%
3rd
98%
5th
95%
5th
Highest
Min
83%
27th
82%
5th
80%
17th
93%
12th
91%
27th
93%
2nd
87%
5th
91%
14th
92%
10th
72%
11th
91%
22nd
72%
1st
Lowest
Max
83%
2nd
83%
25th
87%
24th
86%
5th
83%
24th
87%
23rd
83%
9th
85%
5th
85%
23rd
82%
7th
85%
24th
81%
28th
Lowest
Mean
60%
7th
68%
25th
68%
9th
77%
17th
73%
24th
80%
21st
76%
10th
80%
1st
72%
24th
67%
14th
68%
12th
60%
29th
Highest
Mean
90%
27th
90%
2nd
89%
1st
95%
12th
95%
12th
95%
3rd
91%
5th
94%
8th
94%
10th
88%
27th
94%
22nd
82%
15th
Averages Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
Mean 75% 79% 80% 87% 89% 89% 84% 88% 84% 78% 80% 72%
Mean
Minimum
58% 61% 61% 75% 80% 83% 76% 78% 70% 60% 64% 54%
Mean
Maximum
91% 93% 94% 95% 95% 95% 91% 94% 93% 90% 93% 89%

Past Year Seasonal Averages
Season Daily Min Daily Max Mean
Winter 23/24 79%
93%
87%
Spring 2024 64%
92%
80%
Summer 2023 57%
91%
75%
Autumn 2023 72%
94%
85%

View daily tables of min / max / mean Humidity data for the past year
View monthly tables of min / max / mean Humidity data for all months in the station history.

Latest charts and graphs of Humidity

Past 24hrs and past 12 months trends for Humidity

Last 24hrs London Humidity 12 month mean London Humidity 12month min London Humidity 12month max London Humidity

Current year vs last year daily trends for Humidity

Daily London mean Humidity vs climate normals

This year min/max daily trends in detail for Humidity

Current year daily London min Humidity vs climate normals Current year daily London max Humidity vs climate normals

View more Humidity charts

Record Period Averages
Measure 7-day Month July 31-day Year 365-day
Least
Humid
50%
Ending 9th May 2016
60%
May 2011
61%
2013
58%
Ending 6th May 2011
73%
2016
71%
Ending 17th Jul 2017
Most
Humid
96%
Ending 27th Nov 2014
92%
Dec 2009
78%
Current
93%
Ending 20th Jan 2010
82%
2023
82%
Ending Today
Lowest
Mean
Daily-Min
32%
Ending 19th Jul 2013
40%
May 2020
41%
2018
37%
Ending 21st Jul 2018
57%
2015
56%
Ending 11th Jul 2015
Highest
Mean
Daily-Min
92%
Ending 27th Nov 2014
84%
Dec 2009
63%
Current
86%
Ending 20th Jan 2010
67%
2023
69%
Ending Today
Lowest
Mean
Daily-Max
73%
Ending 25th Apr 2017
76%
Apr 2017
80%
2017
76%
Ending 30th Apr 2017
85%
2016
82%
Ending 2nd Sep 2017
Highest
Mean
Daily-Max
98%
Ending 17th Jan 2010
97%
Dec 2009
92%
Current
97%
Ending 28th Dec 2009
92%
2023
93%
Ending Today

Ranked Historical Humidity Data

Most Humid Days
Rank Min Max Mean
1 98%
23rd Dec 2009
99%
21st Oct 2022
98%
23rd Dec 2009
2 98%
24th Dec 2009
99%
9th Mar 2023
98%
24th Dec 2009
3 98%
30th Dec 2009
99%
13th Nov 2023
98%
30th Dec 2009
4 98%
14th Jan 2010
99%
8th Feb 2024
98%
14th Jan 2010
5 98%
15th Jan 2010
98%
6th Feb 2009
98%
15th Jan 2010
6 98%
29th Dec 2010
98%
9th Feb 2009
98%
29th Dec 2010
7 98%
22nd Oct 2012
98%
10th Feb 2009
98%
30th Dec 2010
8 98%
23rd Oct 2012
98%
13th Feb 2009
98%
20th Nov 2011
9 98%
11th Feb 2013
98%
7th Aug 2009
98%
21st Nov 2011
10 98%
8th Mar 2013
98%
8th Aug 2009
98%
22nd Oct 2012
Least Humid Days
Rank Min Max Mean
1 20%
9th Jun 2021
56%
20th Jul 2010
39%
2nd May 2013
2 20%
19th Jul 2022
56%
2nd May 2013
41%
5th May 2016
3 21%
25th Mar 2017
61%
28th Mar 2012
41%
15th Jul 2013
4 22%
15th Jul 2013
62%
6th Jan 2009
43%
20th Jul 2010
5 22%
18th Jul 2016
63%
21st Feb 2013
43%
28th Mar 2012
6 23%
23rd Apr 2021
63%
2nd Jul 2018
43%
2nd Jul 2018
7 23%
18th Jul 2022
64%
31st Jan 2009
44%
10th Jul 2015
8 24%
8th Sep 2012
65%
2nd Feb 2012
44%
19th Jul 2022
9 24%
30th Jun 2015
65%
27th May 2013
44%
1st Jul 2015
10 24%
10th Jul 2015
65%
1st Jul 2015
45%
17th Jul 2013


Most Humid Months
Rank Min Max Mean
1 84%
Dec 2009
97%
Dec 2009
92%
Dec 2009
2 84%
Dec 2022
96%
Nov 2014
90%
Nov 2014
3 84%
Dec 2020
96%
Feb 2010
90%
Dec 2022
4 83%
Dec 2023
96%
Jan 2014
90%
Jan 2010
5 82%
Jan 2021
95%
Jan 2010
90%
Jan 2021
6 82%
Nov 2022
95%
Oct 2012
89%
Nov 2023
7 82%
Jan 2010
95%
Nov 2011
89%
Dec 2020
8 81%
Dec 2021
95%
Oct 2022
89%
Nov 2022
9 81%
Nov 2014
95%
Nov 2019
89%
Dec 2023
10 80%
Dec 2010
95%
Nov 2019
89%
Nov 2019
Least Humid Months
Rank Min Max Mean
1 40%
May 2020
76%
Apr 2017
60%
May 2011
2 41%
Jul 2018
79%
Jun 2017
60%
Apr 2017
3 42%
Jul 2013
80%
May 2011
61%
Jun 2015
4 42%
May 2011
80%
Apr 2011
61%
Jul 2013
5 42%
Jun 2015
80%
Apr 2011
62%
Apr 2011
6 43%
Jul 2014
80%
Jun 2015
62%
May 2020
7 43%
Jul 2015
80%
Jul 2017
62%
Jul 2018
8 44%
Jun 2014
81%
Jul 2010
63%
Jul 2015
9 44%
Apr 2015
82%
Jul 2015
63%
Jul 2010
10 44%
May 2015
82%
Dec 2016
63%
Jun 2017


Most Humid Days in July
Rank Min Max Mean
1 89%
Day 9, 2024
97%
Day 12, 2009
94%
Day 9, 2024
2 83%
Day 27, 2023
97%
Day 8, 2012
90%
Day 8, 2012
3 82%
Day 11, 2014
97%
Day 6, 2024
90%
Day 25, 2021
4 80%
Day 9, 2020
97%
Day 8, 2024
90%
Day 8, 2020
5 79%
Day 4, 2020
96%
Day 17, 2009
90%
Day 27, 2023
Least Humid Days in July
Rank Min Max Mean
1 20%
Day 19, 2022
56%
Day 20, 2010
41%
Day 15, 2013
2 22%
Day 15, 2013
63%
Day 2, 2018
43%
Day 20, 2010
3 22%
Day 18, 2016
65%
Day 1, 2015
43%
Day 2, 2018
4 23%
Day 18, 2022
65%
Day 11, 2015
44%
Day 10, 2015
5 24%
Day 10, 2015
66%
Day 19, 2010
44%
Day 19, 2022

Notes:

  • Valid humidity records began in February 2009
  • All figures, unless specified, relate to the period midnight-midnight, this being when daily extremes are reset
  • 98% is the physical limit of the hygrometer (measuring RH); in reality this tends to means 100% saturation of the air. This value is achieved fairly frequently, any record with this value is just the first instance it occurred in the relevant timeframe.

The different measures of humidity:
The Dew Point (or frost point if the temperature is < 0.0 °C  is the saturation temperature of a parcel of air, i.e. the point at which water condenses out. It is the temperature at which an object would need to be for dew to form on it (dew forms because certain objects - like cars - cool more rapidly than the air, enabling them to reach the dew point). It is directly proportional to the specific humidity, and very well correlated to the absolute humidity. In everyday terms, high dew points are more uncomfortable as sweating is less effective.
Relative Humidity, on the other hand, is rather more abstract and has a very technical definition: the ratio of the partial pressure of water vapour in the air to the saturated vapour pressure of that water. The saturated vapour pressure is proportional to the air temperature, and the partial pressure indicates how much water vapour the air contains, so at a given temperature, the RH is entirely dependent on this partial pressure, making the RH useful in determining the extent to which the air is water-saturated. For example: When it rains the relative humidity will increase, but the dew point may not, as the temperature will usually fall as well. If the dew point is the same when the RH increases, the air has the same amount of water but it is cooler, so it is more saturated, as less water vapour can exist in cooler air.
Simply and concisely: Dew point is a rough measure of how much water vapour is physically in the air; relative humidity is just a measure of the degree to which the air is full of water vapour (i.e. its saturation). One is an absolute measure, the other is relative.