Humidity Type:
Difference?

Detailed Relative Humidity Data

Current
Measure Value
Relative Humidity 64%
Humidity Trend -2% /hr
24hr Mean Humidity 78%
Wet-Bulb Temperature 6.9 °C
Absolute Humidity 5.97 gm-3
Air Density 1251.62 gm-3
Recent Averages and Extremes
Measure Today Yesterday
Minimum 62%
11:57
60%
17:34
Maximum 88%
03:37
87%
23:44
Mean 81%
76%
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 April 17th Apr
Lowest
Min
44%
14th
44%
14th
44%
14th
44%
14th Apr
34%
16th Jun
20%
9th Jun 2021
23%
Day 23, 2021
27%
2022
Highest
Max
92%
11th
95%
3rd
96%
30th
99%
8th Feb
99%
8th Feb
99%
21st Oct 2022
98%
Day 29, 2012
97%
2009
Highest
Min
72%
11th
72%
11th
84%
19th
92%
10th Mar
93%
3rd Dec
98%
23rd Dec 2009
94%
Day 17, 2009
94%
2009
Lowest
Max
86%
15th
82%
7th
82%
7th
82%
7th Apr
78%
17th Jun
56%
20th Jul 2010
66%
Day 21, 2011
66%
2014
Lowest
Mean
67%
14th
67%
14th
67%
14th
67%
14th Apr
56%
16th Jun
39%
2nd May 2013
48%
Day 21, 2011
54%
2014
Highest
Mean
85%
11th
86%
3rd
88%
31st
94%
8th Feb
95%
12th Oct
98%
23rd Dec 2009
96%
Day 11, 2009
96%
2009
Averages                
Mean 76% 79% 80% 84% 82% 77% 70% 68%
Mean
Minimum
57% 60% 63% 73% 68% 61% 50% 48%
Mean
Maximum
88% 90% 91% 92% 92% 89% 86% 86%

Past Year Monthly Averages and Extremes (April 2023 - March 2024)
Extremes Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar
Lowest
Min
36%
20th
38%
28th
34%
16th
37%
7th
41%
23rd
38%
4th
56%
8th
61%
24th
68%
21st
60%
26th
64%
12th
47%
30th
Highest
Max
97%
22nd
95%
9th
95%
20th
96%
23rd
98%
9th
98%
15th
98%
18th
99%
13th
98%
3rd
96%
1st
99%
8th
97%
4th
Highest
Min
80%
1st
85%
13th
69%
6th
83%
27th
82%
5th
80%
17th
93%
12th
91%
27th
93%
2nd
87%
5th
91%
14th
92%
10th
Lowest
Max
82%
26th
82%
22nd
78%
17th
83%
2nd
83%
25th
87%
24th
86%
5th
83%
24th
87%
23rd
83%
9th
85%
5th
85%
23rd
Lowest
Mean
69%
13th
66%
28th
56%
16th
60%
7th
68%
25th
68%
9th
77%
17th
73%
24th
80%
21st
76%
10th
80%
1st
72%
24th
Highest
Mean
88%
1st
90%
6th
80%
20th
90%
27th
90%
2nd
89%
1st
95%
12th
95%
12th
95%
3rd
91%
5th
94%
8th
94%
10th
Averages Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar
Mean 78% 77% 71% 75% 79% 80% 87% 89% 89% 84% 88% 84%
Mean
Minimum
57% 61% 52% 58% 61% 61% 75% 80% 83% 76% 78% 70%
Mean
Maximum
92% 90% 87% 91% 93% 94% 95% 95% 95% 91% 94% 93%

Past Year Seasonal Averages
Season Daily Min Daily Max Mean
Winter 23/24 79%
93%
87%
Spring 2023 63%
92%
80%
Summer 2023 57%
90%
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 April 31-day Year 365-day
Least
Humid
50%
Ending 9th May 2016
60%
May 2011
60%
2017
58%
Ending 6th May 2011
73%
2016
71%
Ending 17th Jul 2017
Most
Humid
96%
Ending 27th Nov 2014
92%
Dec 2009
79%
Current
93%
Ending 20th Jan 2010
84%
2024
82%
Ending 12th Apr 2024
Lowest
Mean
Daily-Min
32%
Ending 19th Jul 2013
40%
May 2020
44%
2015
37%
Ending 21st Jul 2018
57%
2015
56%
Ending 11th Jul 2015
Highest
Mean
Daily-Min
92%
Ending 27th Nov 2014
84%
Dec 2009
62%
2018
86%
Ending 20th Jan 2010
73%
2024
68%
Ending 12th Apr 2024
Lowest
Mean
Daily-Max
73%
Ending 25th Apr 2017
76%
Apr 2017
76%
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%
2023
97%
Ending 28th Dec 2009
92%
2024
92%
Ending 4th Apr 2024

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 April
Rank Min Max Mean
1 94%
Day 17, 2009
98%
Day 29, 2012
96%
Day 11, 2009
2 93%
Day 11, 2009
98%
Day 11, 2013
96%
Day 17, 2009
3 93%
Day 9, 2018
98%
Day 14, 2013
95%
Day 9, 2018
4 92%
Day 12, 2009
98%
Day 21, 2014
95%
Day 12, 2009
5 91%
Day 12, 2018
97%
Day 11, 2009
95%
Day 12, 2018
Least Humid Days in April
Rank Min Max Mean
1 23%
Day 23, 2021
66%
Day 21, 2011
48%
Day 21, 2011
2 25%
Day 19, 2018
66%
Day 17, 2014
48%
Day 15, 2015
3 25%
Day 5, 2020
67%
Day 25, 2017
48%
Day 25, 2017
4 26%
Day 19, 2011
68%
Day 23, 2017
50%
Day 22, 2011
5 27%
Day 15, 2015
69%
Day 11, 2017
51%
Day 19, 2017

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.