Humidity Type:
Difference?

Detailed Dew Point Data

Current
Measure Value
Dew Point 4.0 °C
Dew Pt Trend -0.1 °C /hr
24hr Mean Dew Pt 3.3 °C
Wet-Bulb Temperature 9.6 °C
Absolute Humidity 6.17 gm-3
Air Density 1240.03 gm-3
Recent Averages and Extremes
Measure Today Yesterday
Minimum 2.2 °C
06:11
1.5 °C
16:40
Maximum 4.8 °C
09:04
5.0 °C
00:06
Mean 3.6 °C
3.0 °C
Last 6hrs  LondonDew Point31-day chart of mean LondonDew Point 31-day chart of min LondonDew Point 31-day chart of max LondonDew Point
Averages, Extremes and Records
Current Station Lifetime (09-24)
Measure 7-day Month 31-day Year 365-day Overall April 18th Apr
Lowest
Min
1.5 °C
17th
1.5 °C
17th
1.5 °C
17th
-7.5 °C
18th Jan
-7.5 °C
18th Jan
-11.5 °C
2nd Feb 2012
-11.0 °C
Day 5, 2021
-3.2 °C
2021
Highest
Max
14.5 °C
12th
14.6 °C
11th
14.6 °C
11th
14.6 °C
11th Apr
22.2 °C
10th Sep
22.2 °C
10th Sep 2023
14.6 °C
Day 22, 2018
13.4 °C
2018
Highest
Min
8.6 °C
13th
11.2 °C
11th
11.2 °C
11th
11.2 °C
11th Apr
16.5 °C
10th Sep
17.6 °C
12th Aug 2020
11.5 °C
Day 6, 2014
5.0 °C
2018
Lowest
Max
4.8 °C
Today
4.8 °C
Today
4.4 °C
23rd
-1.7 °C
18th Jan
-1.7 °C
18th Jan
-7.9 °C
2nd Feb 2012
-2.2 °C
Day 1, 2013
1.3 °C
2017
Lowest
Mean
3.0 °C
17th
3.0 °C
17th
2.6 °C
23rd
-4.6 °C
18th Jan
-4.6 °C
18th Jan
-9.7 °C
2nd Feb 2012
-5.8 °C
Day 2, 2013
-0.8 °C
2017
Highest
Mean
11.0 °C
13th
12.4 °C
11th
12.4 °C
11th
12.4 °C
11th Apr
18.7 °C
10th Sep
19.1 °C
12th Aug 2020
12.4 °C
Day 11, 2024
10.4 °C
2018
Averages                
Mean 6.2 °C 8.1 °C 7.4 °C 5.8 °C 9.3 °C 7.3 °C 4.6 °C 3.8 °C
Mean
Minimum
4.0 °C 6.1 °C 5.3 °C 3.6 °C 6.9 °C 4.7 °C 1.9 °C 0.9 °C
Mean
Maximum
8.8 °C 10.3 °C 9.5 °C 8.0 °C 11.5 °C 9.8 °C 7.4 °C 6.7 °C

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
-1.8 °C
4th
3.5 °C
28th
3.0 °C
14th
7.8 °C
26th
8.7 °C
31st
7.1 °C
23rd
0.0 °C
16th
-3.2 °C
30th
-3.9 °C
2nd
-7.5 °C
18th
-1.0 °C
25th
-1.1 °C
4th
Highest
Max
12.8 °C
28th
14.0 °C
7th
21.2 °C
12th
19.8 °C
8th
19.3 °C
11th
22.2 °C
10th
18.6 °C
1st
13.9 °C
18th
12.3 °C
24th
11.8 °C
2nd
12.5 °C
15th
12.2 °C
17th
Highest
Min
7.0 °C
28th
10.4 °C
7th
15.9 °C
28th
14.8 °C
27th
15.3 °C
18th
16.5 °C
10th
15.0 °C
2nd
8.6 °C
13th
9.0 °C
24th
7.9 °C
29th
10.0 °C
14th
9.0 °C
20th
Lowest
Max
3.2 °C
25th
7.4 °C
3rd
10.1 °C
2nd
11.6 °C
2nd
13.3 °C
6th
11.2 °C
23rd
4.9 °C
15th
0.8 °C
25th
-1.0 °C
2nd
-1.7 °C
18th
4.4 °C
12th
4.4 °C
3rd
Lowest
Mean
1.3 °C
25th
5.7 °C
3rd
7.9 °C
2nd
9.9 °C
2nd
10.9 °C
30th
8.9 °C
23rd
3.0 °C
15th
-1.1 °C
30th
-1.9 °C
2nd
-4.6 °C
18th
2.5 °C
24th
1.8 °C
3rd
Highest
Mean
10.8 °C
28th
12.2 °C
7th
17.1 °C
28th
17.5 °C
8th
17.2 °C
18th
18.7 °C
10th
16.2 °C
2nd
11.1 °C
18th
11.2 °C
24th
9.5 °C
2nd
11.3 °C
15th
10.4 °C
17th
Averages Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar
Mean 5.6 °C 9.2 °C 13.0 °C 13.3 °C 14.0 °C 14.8 °C 11.1 °C 6.2 °C 6.4 °C 2.9 °C 6.9 °C 6.4 °C
Mean
Minimum
2.9 °C 6.9 °C 10.0 °C 11.1 °C 11.9 °C 12.3 °C 8.7 °C 3.9 °C 4.0 °C 0.5 °C 4.7 °C 4.3 °C
Mean
Maximum
7.9 °C 11.6 °C 16.0 °C 15.3 °C 16.2 °C 17.1 °C 13.3 °C 8.5 °C 8.3 °C 5.4 °C 9.1 °C 8.2 °C

Past Year Seasonal Averages
Season Daily Min Daily Max Mean
Winter 23/24 3.1 °C
7.6 °C
5.4 °C
Spring 2023 4.7 °C
9.2 °C
7.1 °C
Summer 2023 11.0 °C
15.9 °C
13.4 °C
Autumn 2023 8.3 °C
13.0 °C
10.7 °C

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

Latest charts and graphs of Dew Point

Past 24hrs and past 12 months trends for Dew Point

Last 24hrs London Dew Point 12 month mean London Dew Point 12month min London Dew Point 12month max London Dew Point

Current year vs last year daily trends for Dew Point

Daily London mean Dew Point vs climate normals

This year min/max daily trends in detail for Dew Point

Current year daily London min Dew Point vs climate normals Current year daily London max Dew Point vs climate normals

View more Dew Point charts

Record Period Averages
Measure 7-day Month April 31-day Year 365-day
Least
Humid
-5.2 °C
Ending 31st Mar 2013
-0.8 °C
Jan 2009
1.4 °C
2021
-2.3 °C
Ending 9th Apr 2013
5.8 °C
2010
5.5 °C
Ending 18th Jul 2013
Most
Humid
18.0 °C
Ending 16th Aug 2020
14.8 °C
Sep 2023
8.1 °C
Current
15.2 °C
Ending 12th Sep 2023
8.9 °C
2023
9.3 °C
Ending 13th Apr 2024
Lowest
Mean
Daily-Min
-7.3 °C
Ending 2nd Apr 2013
-3.3 °C
Dec 2010
-1.6 °C
2021
-4.9 °C
Ending 9th Apr 2013
3.2 °C
2010
2.9 °C
Ending 18th Jul 2013
Highest
Mean
Daily-Min
16.4 °C
Ending 16th Aug 2020
12.4 °C
Jul 2021
6.1 °C
Current
13.0 °C
Ending 11th Sep 2023
6.5 °C
2023
7.0 °C
Ending 13th Apr 2024
Lowest
Mean
Daily-Max
-3.0 °C
Ending 31st Mar 2013
1.6 °C
Dec 2010
4.1 °C
2021
0.3 °C
Ending 9th Apr 2013
8.0 °C
2024
8.2 °C
Ending 27th Dec 2010
Highest
Mean
Daily-Max
20.6 °C
Ending 11th Sep 2023
17.1 °C
Sep 2023
10.3 °C
Current
17.5 °C
Ending 12th Sep 2023
11.2 °C
2023
11.6 °C
Ending 13th Apr 2024

Ranked Historical Dew Point Data

Most Humid Days
Rank Min Max Mean
1 17.6 °C
12th Aug 2020
22.2 °C
10th Sep 2023
19.1 °C
12th Aug 2020
2 17.5 °C
11th Aug 2020
21.7 °C
8th Sep 2023
19.0 °C
6th Sep 2016
3 16.9 °C
13th Aug 2020
21.6 °C
6th Sep 2023
18.8 °C
11th Aug 2020
4 16.8 °C
21st Aug 2010
21.5 °C
19th Jul 2021
18.7 °C
10th Sep 2023
5 16.8 °C
6th Sep 2016
21.2 °C
12th Aug 2020
18.6 °C
8th Sep 2023
6 16.8 °C
23rd Aug 2022
21.2 °C
12th Jun 2023
18.5 °C
13th Aug 2020
7 16.6 °C
24th Aug 2022
21.1 °C
25th Jul 2019
18.4 °C
10th Aug 2020
8 16.5 °C
10th Sep 2023
21.1 °C
9th Sep 2023
18.3 °C
19th Jul 2021
9 16.3 °C
7th Sep 2023
20.9 °C
27th Jul 2018
18.2 °C
7th Sep 2023
10 16.2 °C
10th Aug 2020
20.9 °C
21st Jul 2021
18.2 °C
23rd Aug 2022
Least Humid Days
Rank Min Max Mean
1 -11.5 °C
2nd Feb 2012
-7.9 °C
2nd Feb 2012
-9.7 °C
2nd Feb 2012
2 -11.0 °C
5th Apr 2021
-6.2 °C
3rd Feb 2012
-7.8 °C
3rd Feb 2012
3 -10.4 °C
7th Feb 2012
-5.1 °C
13th Feb 2021
-7.2 °C
13th Feb 2021
4 -10.3 °C
12th Mar 2013
-5.0 °C
22nd Feb 2013
-7.2 °C
11th Feb 2012
5 -10.2 °C
11th Feb 2012
-5.0 °C
28th Feb 2018
-6.9 °C
22nd Feb 2013
6 -9.5 °C
1st Feb 2009
-4.5 °C
21st Feb 2013
-6.9 °C
21st Feb 2013
7 -9.4 °C
25th Mar 2017
-4.5 °C
26th Mar 2013
-6.8 °C
28th Feb 2018
8 -9.3 °C
20th Dec 2010
-4.4 °C
25th Mar 2013
-6.7 °C
12th Mar 2013
9 -9.3 °C
2nd Apr 2013
-4.3 °C
12th Feb 2021
-6.3 °C
7th Mar 2010
10 -9.3 °C
28th Feb 2018
-4.1 °C
2nd Feb 2015
-6.0 °C
1st Feb 2012


Most Humid Months
Rank Min Max Mean
1 12.4 °C
Jul 2021
17.1 °C
Sep 2023
14.8 °C
Sep 2023
2 12.3 °C
Aug 2020
16.8 °C
Jul 2021
14.7 °C
Jul 2021
3 12.3 °C
Sep 2023
16.7 °C
Aug 2022
14.4 °C
Aug 2020
4 12.1 °C
Aug 2022
16.6 °C
Aug 2020
14.4 °C
Aug 2022
5 11.9 °C
Aug 2023
16.2 °C
Aug 2023
14.0 °C
Aug 2023
6 11.4 °C
Aug 2021
16.1 °C
Jul 2018
13.5 °C
Jul 2019
7 11.3 °C
Aug 2019
16.0 °C
Jun 2023
13.5 °C
Jul 2022
8 11.2 °C
Jul 2022
15.8 °C
Sep 2021
13.5 °C
Jul 2018
9 11.1 °C
Jul 2023
15.7 °C
Aug 2019
13.5 °C
Sep 2021
10 11.0 °C
Jul 2019
15.7 °C
Jul 2019
13.5 °C
Aug 2019
Least Humid Months
Rank Min Max Mean
1 -3.3 °C
Dec 2010
1.6 °C
Dec 2010
-0.8 °C
Jan 2009
2 -3.0 °C
Mar 2013
1.8 °C
Mar 2013
-0.6 °C
Mar 2013
3 -2.9 °C
Feb 2013
2.2 °C
Jan 2010
-0.5 °C
Dec 2010
4 -2.4 °C
Feb 2018
2.5 °C
Feb 2013
-0.4 °C
Feb 2013
5 -2.4 °C
Jan 2017
2.5 °C
Feb 2018
0.0 °C
Feb 2018
6 -2.2 °C
Feb 2012
3.0 °C
Feb 2012
0.2 °C
Jan 2010
7 -1.7 °C
Jan 2010
3.3 °C
Jan 2017
0.4 °C
Jan 2017
8 -1.6 °C
Apr 2021
4.0 °C
Feb 2015
0.5 °C
Feb 2012
9 -1.6 °C
Feb 2015
4.0 °C
Feb 2009
1.4 °C
Apr 2021
10 -1.5 °C
Feb 2016
4.1 °C
Jan 2019
1.5 °C
Feb 2015


Most Humid Days in April
Rank Min Max Mean
1 11.5 °C
Day 6, 2014
14.6 °C
Day 22, 2018
12.4 °C
Day 11, 2024
2 11.2 °C
Day 11, 2024
14.6 °C
Day 11, 2024
12.2 °C
Day 6, 2014
3 10.3 °C
Day 5, 2024
14.5 °C
Day 15, 2009
11.8 °C
Day 22, 2018
4 9.6 °C
Day 20, 2018
14.5 °C
Day 12, 2024
11.6 °C
Day 6, 2024
5 9.5 °C
Day 6, 2024
14.1 °C
Day 20, 2018
11.5 °C
Day 20, 2018
Least Humid Days in April
Rank Min Max Mean
1 -11.0 °C
Day 5, 2021
-2.2 °C
Day 1, 2013
-5.8 °C
Day 2, 2013
2 -9.3 °C
Day 2, 2013
-1.6 °C
Day 6, 2021
-4.8 °C
Day 3, 2013
3 -7.6 °C
Day 6, 2021
-1.5 °C
Day 3, 2013
-4.6 °C
Day 1, 2013
4 -7.2 °C
Day 1, 2013
-1.3 °C
Day 7, 2021
-4.4 °C
Day 25, 2017
5 -7.0 °C
Day 3, 2013
-1.2 °C
Day 25, 2017
-4.0 °C
Day 6, 2021

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.