London weather in September
In September, London sees average daytime highs of 21°C and overnight lows near 11°C, with 86 mm of rain across 9.7 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.
Highs ease over the month, from about 24°C in the first days to 19°C by the end. The sky is clear or mostly clear about 36% of the time in September, and the air most often feels dry.
Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is London's 2nd-clearest and 9th-windiest month. For the whole year in context, see London's year-round climate.
- Daytime high
- 21°
- 4th warmest
- Overnight low
- 11°
- 9th coldest
- Rainfall
- 86 mm
- 9.7 wet days
- Daylight
- 12 h 18 min
- 6:11 AM – 6:28 PM
- Cloud cover
- 55%
- 2nd clearest
- Wind
- 11 km/h
- 9th windiest
- Solar energy
- 4.33 kWh/m²
- Travel score
- 6.6
- out of 10
London is city in Southwestern Ontario, Canada.
- Air quality
- Good
- PM2.5 7 µg/m³ · 2019
- Density
- 1,004/km²
- people per km²
- Founded
- 1826
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in September
Highs ease over the month, from about 24°C in the first days to 19°C by the end.
A typical September day in London reaches about 21°C in the afternoon and slips back to 11°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 27°C. Set against its neighbours, September runs about 4°C cooler than August and about 7°C warmer than October.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 24 | 24 | 24 | 24 | 23 | 23 | 23 | 23 | 23 | 23 | 22 | 22 | 22 | 22 | 22 | 21 | 21 | 21 | 21 | 21 | 20 | 20 | 20 | 20 | 19 | 19 | 19 | 19 | 18 | 18 |
| Avg low (°C) | 14 | 14 | 14 | 13 | 13 | 13 | 13 | 13 | 13 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 | 9 | 9 | 9 |
| Avg high (°C) | Avg low (°C) | |
|---|---|---|
| 1 | 24 | 14 |
| 2 | 24 | 14 |
| 3 | 24 | 14 |
| 4 | 24 | 13 |
| 5 | 23 | 13 |
| 6 | 23 | 13 |
| 7 | 23 | 13 |
| 8 | 23 | 13 |
| 9 | 23 | 13 |
| 10 | 23 | 12 |
| 11 | 22 | 12 |
| 12 | 22 | 12 |
| 13 | 22 | 12 |
| 14 | 22 | 12 |
| 15 | 22 | 11 |
| 16 | 21 | 11 |
| 17 | 21 | 11 |
| 18 | 21 | 11 |
| 19 | 21 | 11 |
| 20 | 21 | 10 |
| 21 | 20 | 10 |
| 22 | 20 | 10 |
| 23 | 20 | 10 |
| 24 | 20 | 10 |
| 25 | 19 | 9 |
| 26 | 19 | 9 |
| 27 | 19 | 9 |
| 28 | 19 | 9 |
| 29 | 18 | 9 |
| 30 | 18 | 9 |
How September really feels in London
Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.
September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
London weather by month
How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | -1° / -8° | 72 | 11.7 | 9.6 | 9.2 | 0.0 |
| Feb | -0° / -9° | 58 | 9.5 | 8.2 | 10.2 | 0.0 |
| Mar | 5° / -4° | 70 | 10.9 | 5.7 | 11.6 | 0.4 |
| Apr | 12° / 3° | 93 | 12.4 | 2.2 | 13.1 | 3.1 |
| May | 19° / 8° | 98 | 12.5 | 0 | 14.4 | 5.6 |
| Jun | 24° / 14° | 102 | 12 | 0 | 15.1 | 6.5 |
| Jul | 26° / 16° | 100 | 11.9 | 0 | 14.8 | 6.5 |
| Aug | 25° / 15° | 84 | 10.6 | 0 | 13.8 | 6.8 |
| Sep | 21° / 11° | 86 | 9.7 | 0 | 12.3 | 6.6 |
| Oct | 14° / 6° | 86 | 11.8 | 0.2 | 10.8 | 4.1 |
| Nov | 7° / 0° | 77 | 11.1 | 3.9 | 9.5 | 1.0 |
| Dec | 2° / -5° | 68 | 11.2 | 8.1 | 8.9 | 0.0 |
Cloud cover in September
The sky is clear or mostly clear about 36% of the time in September.
Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 47%.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 56 | 56 | 56 | 57 | 57 | 57 | 56 | 56 | 56 | 55 | 55 | 54 | 54 | 54 | 53 | 53 | 53 | 53 | 52 | 52 | 52 | 51 | 51 | 50 | 50 | 50 | 48 | 48 | 48 | 48 |
| Cloudier (%) | 44 | 44 | 44 | 43 | 43 | 43 | 44 | 44 | 44 | 45 | 45 | 46 | 46 | 46 | 47 | 47 | 47 | 47 | 48 | 48 | 48 | 49 | 49 | 50 | 50 | 50 | 52 | 52 | 52 | 52 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 56 | 44 |
| 2 | 56 | 44 |
| 3 | 56 | 44 |
| 4 | 57 | 43 |
| 5 | 57 | 43 |
| 6 | 57 | 43 |
| 7 | 56 | 44 |
| 8 | 56 | 44 |
| 9 | 56 | 44 |
| 10 | 55 | 45 |
| 11 | 55 | 45 |
| 12 | 54 | 46 |
| 13 | 54 | 46 |
| 14 | 54 | 46 |
| 15 | 53 | 47 |
| 16 | 53 | 47 |
| 17 | 53 | 47 |
| 18 | 53 | 47 |
| 19 | 52 | 48 |
| 20 | 52 | 48 |
| 21 | 52 | 48 |
| 22 | 51 | 49 |
| 23 | 51 | 49 |
| 24 | 50 | 50 |
| 25 | 50 | 50 |
| 26 | 50 | 50 |
| 27 | 48 | 52 |
| 28 | 48 | 52 |
| 29 | 48 | 52 |
| 30 | 48 | 52 |
Chance of precipitation in September
London gets around 86 mm of rain over 9.7 wet days in September. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 33% and peaks near 37% on the wettest days.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 32 | 32 | 32 | 33 | 33 | 33 | 33 | 33 | 33 | 32 | 32 | 32 | 32 | 31 | 31 | 31 | 31 | 30 | 30 | 31 | 31 | 32 | 32 | 33 | 34 | 35 | 36 | 36 | 37 | 37 |
| Rain chance (%) | |
|---|---|
| 1 | 32 |
| 2 | 32 |
| 3 | 32 |
| 4 | 33 |
| 5 | 33 |
| 6 | 33 |
| 7 | 33 |
| 8 | 33 |
| 9 | 33 |
| 10 | 32 |
| 11 | 32 |
| 12 | 32 |
| 13 | 32 |
| 14 | 31 |
| 15 | 31 |
| 16 | 31 |
| 17 | 31 |
| 18 | 30 |
| 19 | 30 |
| 20 | 31 |
| 21 | 31 |
| 22 | 32 |
| 23 | 32 |
| 24 | 33 |
| 25 | 34 |
| 26 | 35 |
| 27 | 36 |
| 28 | 36 |
| 29 | 37 |
| 30 | 37 |
Humidity in September
Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, September lands in the dry band about 57% of days. Sticky, muggy-or-worse air turns up on roughly 9% of them.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 35 | 37 | 38 | 40 | 41 | 43 | 44 | 46 | 47 | 49 | 50 | 52 | 53 | 53 | 56 | 57 | 59 | 61 | 63 | 64 | 67 | 67 | 70 | 71 | 72 | 74 | 74 | 76 | 76 | 78 |
| Comfortable (%) | 27 | 27 | 26 | 26 | 26 | 26 | 25 | 25 | 25 | 24 | 24 | 23 | 23 | 23 | 22 | 22 | 21 | 20 | 19 | 18 | 17 | 17 | 16 | 15 | 15 | 14 | 14 | 13 | 13 | 12 |
| Humid (%) | 19 | 18 | 17 | 17 | 17 | 16 | 16 | 16 | 16 | 16 | 15 | 15 | 15 | 15 | 14 | 14 | 13 | 13 | 12 | 12 | 11 | 11 | 10 | 10 | 9 | 9 | 9 | 8 | 8 | 8 |
| Muggy (%) | 17 | 16 | 16 | 15 | 14 | 13 | 12 | 12 | 11 | 10 | 10 | 9 | 8 | 8 | 8 | 7 | 7 | 6 | 6 | 6 | 5 | 5 | 4 | 4 | 4 | 3 | 3 | 3 | 3 | 2 |
| Oppressive (%) | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | Muggy (%) | Oppressive (%) | |
|---|---|---|---|---|---|
| 1 | 35 | 27 | 19 | 17 | 2 |
| 2 | 37 | 27 | 18 | 16 | 2 |
| 3 | 38 | 26 | 17 | 16 | 2 |
| 4 | 40 | 26 | 17 | 15 | 2 |
| 5 | 41 | 26 | 17 | 14 | 2 |
| 6 | 43 | 26 | 16 | 13 | 2 |
| 7 | 44 | 25 | 16 | 12 | 2 |
| 8 | 46 | 25 | 16 | 12 | 2 |
| 9 | 47 | 25 | 16 | 11 | 1 |
| 10 | 49 | 24 | 16 | 10 | 1 |
| 11 | 50 | 24 | 15 | 10 | 1 |
| 12 | 52 | 23 | 15 | 9 | 1 |
| 13 | 53 | 23 | 15 | 8 | 1 |
| 14 | 53 | 23 | 15 | 8 | 1 |
| 15 | 56 | 22 | 14 | 8 | 0 |
| 16 | 57 | 22 | 14 | 7 | 0 |
| 17 | 59 | 21 | 13 | 7 | 0 |
| 18 | 61 | 20 | 13 | 6 | 0 |
| 19 | 63 | 19 | 12 | 6 | 0 |
| 20 | 64 | 18 | 12 | 6 | 0 |
| 21 | 67 | 17 | 11 | 5 | 0 |
| 22 | 67 | 17 | 11 | 5 | 0 |
| 23 | 70 | 16 | 10 | 4 | 0 |
| 24 | 71 | 15 | 10 | 4 | 0 |
| 25 | 72 | 15 | 9 | 4 | 0 |
| 26 | 74 | 14 | 9 | 3 | 0 |
| 27 | 74 | 14 | 9 | 3 | 0 |
| 28 | 76 | 13 | 8 | 3 | 0 |
| 29 | 76 | 13 | 8 | 3 | 0 |
| 30 | 78 | 12 | 8 | 2 | 0 |
Wind in September
Winds average 11 km/h in September.
Across September, daily wind ranges from about 11 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 11 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | light breeze | light breeze | light breeze | light breeze | light breeze | light breeze |
| Wind speed (km/h) | Feels | |
|---|---|---|
| 1 | 11 | calm |
| 2 | 11 | calm |
| 3 | 11 | calm |
| 4 | 11 | calm |
| 5 | 11 | calm |
| 6 | 11 | calm |
| 7 | 11 | calm |
| 8 | 11 | calm |
| 9 | 11 | calm |
| 10 | 11 | calm |
| 11 | 11 | calm |
| 12 | 11 | calm |
| 13 | 11 | calm |
| 14 | 11 | calm |
| 15 | 11 | calm |
| 16 | 11 | calm |
| 17 | 11 | calm |
| 18 | 11 | calm |
| 19 | 12 | calm |
| 20 | 12 | calm |
| 21 | 12 | calm |
| 22 | 12 | calm |
| 23 | 12 | calm |
| 24 | 12 | calm |
| 25 | 12 | light breeze |
| 26 | 12 | light breeze |
| 27 | 12 | light breeze |
| 28 | 12 | light breeze |
| 29 | 12 | light breeze |
| 30 | 12 | light breeze |
Sunrise & sunset in September
Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 84 minutes over September. Sunrise moves from 5:54 AM to 6:27 AM, and sunset from 6:55 PM to 6:02 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 13.0 | 13.0 | 12.9 | 12.9 | 12.8 | 12.8 | 12.7 | 12.7 | 12.6 | 12.6 | 12.5 | 12.5 | 12.4 | 12.4 | 12.3 | 12.3 | 12.2 | 12.2 | 12.1 | 12.1 | 12.0 | 12.0 | 11.9 | 11.9 | 11.8 | 11.8 | 11.7 | 11.7 | 11.6 | 11.6 |
| Sunrise (AM) | 5:54 | 5:55 | 5:56 | 5:57 | 5:58 | 5:59 | 6:01 | 6:02 | 6:03 | 6:04 | 6:05 | 6:06 | 6:07 | 6:08 | 6:09 | 6:11 | 6:12 | 6:13 | 6:14 | 6:15 | 6:16 | 6:17 | 6:19 | 6:20 | 6:21 | 6:22 | 6:23 | 6:24 | 6:25 | 6:27 |
| Sunset (PM) | 6:55 | 6:54 | 6:52 | 6:50 | 6:48 | 6:46 | 6:45 | 6:43 | 6:41 | 6:39 | 6:37 | 6:35 | 6:34 | 6:32 | 6:30 | 6:28 | 6:26 | 6:24 | 6:22 | 6:20 | 6:19 | 6:17 | 6:15 | 6:13 | 6:11 | 6:09 | 6:07 | 6:06 | 6:04 | 6:02 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 13.0 | 5:54 | 6:55 |
| 2 | 13.0 | 5:55 | 6:54 |
| 3 | 12.9 | 5:56 | 6:52 |
| 4 | 12.9 | 5:57 | 6:50 |
| 5 | 12.8 | 5:58 | 6:48 |
| 6 | 12.8 | 5:59 | 6:46 |
| 7 | 12.7 | 6:01 | 6:45 |
| 8 | 12.7 | 6:02 | 6:43 |
| 9 | 12.6 | 6:03 | 6:41 |
| 10 | 12.6 | 6:04 | 6:39 |
| 11 | 12.5 | 6:05 | 6:37 |
| 12 | 12.5 | 6:06 | 6:35 |
| 13 | 12.4 | 6:07 | 6:34 |
| 14 | 12.4 | 6:08 | 6:32 |
| 15 | 12.3 | 6:09 | 6:30 |
| 16 | 12.3 | 6:11 | 6:28 |
| 17 | 12.2 | 6:12 | 6:26 |
| 18 | 12.2 | 6:13 | 6:24 |
| 19 | 12.1 | 6:14 | 6:22 |
| 20 | 12.1 | 6:15 | 6:20 |
| 21 | 12.0 | 6:16 | 6:19 |
| 22 | 12.0 | 6:17 | 6:17 |
| 23 | 11.9 | 6:19 | 6:15 |
| 24 | 11.9 | 6:20 | 6:13 |
| 25 | 11.8 | 6:21 | 6:11 |
| 26 | 11.8 | 6:22 | 6:09 |
| 27 | 11.7 | 6:23 | 6:07 |
| 28 | 11.7 | 6:24 | 6:06 |
| 29 | 11.6 | 6:25 | 6:04 |
| 30 | 11.6 | 6:27 | 6:02 |
Solar energy in September
Average shortwave solar energy reaching the ground each day in September, about 4.33 kWh/m².
For context, solar energy here swings from a low near 1.32 kWh/m² to a high of 6.57 kWh/m² in June across the year — September's 4.33 kWh/m² falls in the middle.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 5.0 | 4.9 | 4.9 | 4.8 | 4.8 | 4.7 | 4.7 | 4.7 | 4.6 | 4.5 | 4.5 | 4.5 | 4.4 | 4.4 | 4.3 | 4.3 | 4.3 | 4.2 | 4.2 | 4.1 | 4.1 | 4.0 | 4.0 | 3.9 | 3.9 | 3.8 | 3.8 | 3.7 | 3.7 | 3.6 |
| Level | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 5.0 | Bright |
| 2 | 4.9 | Bright |
| 3 | 4.9 | Bright |
| 4 | 4.8 | Bright |
| 5 | 4.8 | Bright |
| 6 | 4.7 | Bright |
| 7 | 4.7 | Bright |
| 8 | 4.7 | Bright |
| 9 | 4.6 | Bright |
| 10 | 4.5 | Bright |
| 11 | 4.5 | Bright |
| 12 | 4.5 | Bright |
| 13 | 4.4 | Bright |
| 14 | 4.4 | Bright |
| 15 | 4.3 | Bright |
| 16 | 4.3 | Bright |
| 17 | 4.3 | Bright |
| 18 | 4.2 | Bright |
| 19 | 4.2 | Bright |
| 20 | 4.1 | Bright |
| 21 | 4.1 | Bright |
| 22 | 4.0 | Bright |
| 23 | 4.0 | Moderate |
| 24 | 3.9 | Moderate |
| 25 | 3.9 | Moderate |
| 26 | 3.8 | Moderate |
| 27 | 3.8 | Moderate |
| 28 | 3.7 | Moderate |
| 29 | 3.7 | Moderate |
| 30 | 3.6 | Moderate |
Is September a good time to visit London?
Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
September is a reasonable time to visit London for sightseeing.
What to pack for London in September
From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In September, London sees daytime highs around 21°C and nights near 11°C. Worth packing: rain gear. About 10 days see rain.
Sea temperature near London in September
The nearest coast averages about 21°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 41 km away) is warmest in August at about 23°C and coldest in February near 1°C.
It's comfortable for a long swim from Jul 5 to Sep 20 — about 2.6 months when the water holds above 20°C.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 2 | 1 | 1 | 4 | 10 | 17 | 22 | 23 | 21 | 16 | 10 | 5 |
| Comfort | Bracing | Bracing | Bracing | Bracing | Bracing | Cool | Refreshing | Refreshing | Refreshing | Cool | Bracing | Bracing |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 2 | Bracing |
| Feb | 1 | Bracing |
| Mar | 1 | Bracing |
| Apr | 4 | Bracing |
| May | 10 | Bracing |
| Jun | 17 | Cool |
| Jul | 22 | Refreshing |
| Aug | 23 | Refreshing |
| Sep | 21 | Refreshing |
| Oct | 16 | Cool |
| Nov | 10 | Bracing |
| Dec | 5 | Bracing |
UV index in London in September
Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in London peaks around June 23 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 2 | 4 | 5 | 7 | 9 | 9 | 7 | 6 | 3 | 2 | 1 |
| Level | Low | Moderate | Moderate | High | High | Very high | Very high | High | High | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 2 | Moderate |
| Mar | 4 | Moderate |
| Apr | 5 | High |
| May | 7 | High |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 7 | High |
| Sep | 6 | High |
| Oct | 3 | Moderate |
| Nov | 2 | Low |
| Dec | 1 | Low |
Where is London?
London sits at 43.0°N, 81.2°W, 252 m above sea level, in Canada. The nearest listed city is St. Thomas, 24 km away.
Topography around London
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of London.
Within 3 km, the terrain around London has only modest variations in elevation — a maximum elevation change of 62 m around an average of 253 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 118 m; within 80 km, significant variations in elevation — a maximum elevation change of 271 m.
The land around London is covered by artificial surfaces (53%) and trees (36%) within 3 km, cropland (48%) and trees (24%) within 16 km, and cropland (57%) and water (22%) within 80 km.
Canada travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 83% of US
- price level, 2025
- GDP per capita
- $55,698
- 2025
- Happiness
- 6.7 / 10
- World Happiness, 2025
- Safe drinking water
- 97%
- of population, 2024
- Homicide rate
- 2
- per 100k, 2023
- Road deaths
- 5.3
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for London (42.9834°, -81.233°, elevation 252 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).