Isle of Lewis weather in September

In September, Isle of Lewis sees average daytime highs of 15°C and overnight lows near 10°C, with 89 mm of rain across 15.8 wet days and about 12.5 hours of daylight. It is the 3rd-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 16°C in the first days to 14°C by the end. The sky is clear or mostly clear about 6% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 48 min at the start of September to 11 h 18 min by month's end. Set against the rest of the year, September is Isle of Lewis's 9th-clearest and 8th-windiest month. For the whole year in context, see Isle of Lewis's year-round climate.

Daytime high: 15°; 3rd warmest
Overnight low: 10°; 10th coldest
Rainfall: 89 mm; 15.8 wet days
Daylight: 12 h 30 min; 6:05 AM – 6:35 PM
Cloud cover: 79%; 9th clearest
Wind: 19 km/h; 8th windiest
Solar energy: 2.52 kWh/m²
Travel score: 3.7; out of 10

← August Isle of Lewis year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 16°C in the first days to 14°C by the end.

A typical September day in Isle of Lewis reaches about 15°C in the afternoon and slips back to 10°C overnight — a 5°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 18°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°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)	16	16	16	16	16	16	16	16	16	16	15	15	15	15	15	15	15	15	15	15	15	15	15	14	14	14	14	14	14	14
Avg low (°C)	11	11	11	11	11	11	11	11	11	10	10	10	10	10	10	10	10	10	10	10	10	10	10	9	9	9	9	9	9	9

	Avg high (°C)	Avg low (°C)
1	16	11
2	16	11
3	16	11
4	16	11
5	16	11
6	16	11
7	16	11
8	16	11
9	16	11
10	16	10
11	15	10
12	15	10
13	15	10
14	15	10
15	15	10
16	15	10
17	15	10
18	15	10
19	15	10
20	15	10
21	15	10
22	15	10
23	15	10
24	14	9
25	14	9
26	14	9
27	14	9
28	14	9
29	14	9
30	14	9

How September really feels in Isle of Lewis

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.

Days feeling ≥ 32°C

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Isle of Lewis weather by month

How September compares with the rest of the year at a glance. September is the 3rd-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	8° / 4°	100	16.2	1.1	6.9	1.0
Feb	8° / 4°	80	14.8	2	8.9	1.1
Mar	9° / 4°	84	16.8	1.3	11.4	1.4
Apr	11° / 5°	74	16.1	0.4	14	2.2
May	13° / 7°	76	16.8	0	16.4	3.0
Jun	15° / 10°	79	16.6	0	17.8	3.6
Jul	17° / 11°	88	18.6	0	17.2	4.1
Aug	17° / 11°	94	17.9	0	15.1	4.2
Sep	15° / 10°	89	15.8	0	12.5	3.7
Oct	12° / 8°	103	17.6	0	9.9	2.7
Nov	10° / 6°	91	16.3	0.2	7.5	1.7
Dec	8° / 4°	90	15.7	1	6.2	1.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 6% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 81%.

	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 (%)	17	17	17	17	17	17	16	16	16	16	18	18	18	19	19	19	19	21	21	21	20	20	20	21	21	21	21	21	21	21
Cloudier (%)	83	83	83	83	83	83	84	84	84	84	82	82	82	81	81	81	81	79	79	79	80	80	80	79	79	79	79	79	79	79

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	16	84
8	16	84
9	16	84
10	16	84
11	18	82
12	18	82
13	18	82
14	19	81
15	19	81
16	19	81
17	19	81
18	21	79
19	21	79
20	21	79
21	20	80
22	20	80
23	20	80
24	21	79
25	21	79
26	21	79
27	21	79
28	21	79
29	21	79
30	21	79

Chance of precipitation in September

Any precipitation

Isle of Lewis gets around 89 mm of rain over 15.8 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 53% and peaks near 56% 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 (%)	55	54	55	55	55	55	55	55	54	54	54	53	53	53	53	52	52	52	51	51	50	50	51	51	52	53	53	54	55	56

	Rain chance (%)
1	55
2	54
3	55
4	55
5	55
6	55
7	55
8	55
9	54
10	54
11	54
12	53
13	53
14	53
15	53
16	52
17	52
18	52
19	51
20	51
21	50
22	50
23	51
24	51
25	52
26	53
27	53
28	54
29	55
30	56

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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 93% of days. It rarely turns muggy — the humid and sticky bands barely register.

	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 (%)	89	90	90	90	90	90	90	91	91	92	92	93	93	93	94	94	94	94	95	95	95	95	95	95	95	96	96	96	96	96
Comfortable (%)	11	10	10	10	10	10	10	9	9	8	8	7	7	7	6	6	6	6	5	5	5	5	5	5	5	4	4	4	4	4

	Dry (%)	Comfortable (%)
1	89	11
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	90	10
8	91	9
9	91	9
10	92	8
11	92	8
12	93	7
13	93	7
14	93	7
15	94	6
16	94	6
17	94	6
18	94	6
19	95	5
20	95	5
21	95	5
22	95	5
23	95	5
24	95	5
25	95	5
26	96	4
27	96	4
28	96	4
29	96	4
30	96	4

Wind in September

Winds average 19 km/h in September.

Across September, daily wind ranges from about 18 km/h on the calmest days to 20 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)	18	18	18	18	18	18	18	18	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	19	20	20
Feels	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze	light breeze

	Wind speed (km/h)	Feels
1	18	light breeze
2	18	light breeze
3	18	light breeze
4	18	light breeze
5	18	light breeze
6	18	light breeze
7	18	light breeze
8	18	light breeze
9	19	light breeze
10	19	light breeze
11	19	light breeze
12	19	light breeze
13	19	light breeze
14	19	light breeze
15	19	light breeze
16	19	light breeze
17	19	light breeze
18	19	light breeze
19	19	light breeze
20	19	light breeze
21	19	light breeze
22	19	light breeze
23	19	light breeze
24	19	light breeze
25	19	light breeze
26	19	light breeze
27	19	light breeze
28	19	light breeze
29	20	light breeze
30	20	light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 48 min at the start of September to 11 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 150 minutes over September. Sunrise moves from 5:31 AM to 6:36 AM, and sunset from 7:19 PM to 5:53 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)	13.8	13.7	13.6	13.5	13.4	13.4	13.3	13.2	13.1	13.0	12.9	12.8	12.8	12.7	12.6	12.5	12.4	12.3	12.2	12.2	12.1	12.0	11.9	11.8	11.7	11.6	11.5	11.5	11.4	11.3
Sunrise (AM)	5:31	5:34	5:36	5:38	5:40	5:43	5:45	5:47	5:49	5:52	5:54	5:56	5:58	6:00	6:03	6:05	6:07	6:09	6:12	6:14	6:16	6:18	6:21	6:23	6:25	6:27	6:30	6:32	6:34	6:36
Sunset (PM)	7:19	7:16	7:13	7:10	7:07	7:04	7:02	6:59	6:56	6:53	6:50	6:47	6:44	6:41	6:38	6:35	6:32	6:29	6:26	6:23	6:20	6:17	6:14	6:11	6:08	6:05	6:02	5:59	5:56	5:53

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.8	5:31	7:19
2	13.7	5:34	7:16
3	13.6	5:36	7:13
4	13.5	5:38	7:10
5	13.4	5:40	7:07
6	13.4	5:43	7:04
7	13.3	5:45	7:02
8	13.2	5:47	6:59
9	13.1	5:49	6:56
10	13.0	5:52	6:53
11	12.9	5:54	6:50
12	12.8	5:56	6:47
13	12.8	5:58	6:44
14	12.7	6:00	6:41
15	12.6	6:03	6:38
16	12.5	6:05	6:35
17	12.4	6:07	6:32
18	12.3	6:09	6:29
19	12.2	6:12	6:26
20	12.2	6:14	6:23
21	12.1	6:16	6:20
22	12.0	6:18	6:17
23	11.9	6:21	6:14
24	11.8	6:23	6:11
25	11.7	6:25	6:08
26	11.6	6:27	6:05
27	11.5	6:30	6:02
28	11.5	6:32	5:59
29	11.4	6:34	5:56
30	11.3	6:36	5:53

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.52 kWh/m².

For context, solar energy here swings from a low near 0.27 kWh/m² to a high of 5.2 kWh/m² in June across the year — September's 2.52 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)	3.2	3.1	3.1	3.0	3.0	2.9	2.9	2.9	2.8	2.8	2.7	2.7	2.6	2.6	2.5	2.5	2.5	2.4	2.4	2.3	2.3	2.3	2.2	2.2	2.1	2.1	2.0	2.0	1.9	1.9
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Dim	Dim

	Solar energy (kWh/m²)	Level
1	3.2	Moderate
2	3.1	Moderate
3	3.1	Moderate
4	3.0	Moderate
5	3.0	Moderate
6	2.9	Moderate
7	2.9	Moderate
8	2.9	Moderate
9	2.8	Moderate
10	2.8	Moderate
11	2.7	Moderate
12	2.7	Moderate
13	2.6	Moderate
14	2.6	Moderate
15	2.5	Moderate
16	2.5	Moderate
17	2.5	Moderate
18	2.4	Moderate
19	2.4	Moderate
20	2.3	Moderate
21	2.3	Moderate
22	2.3	Moderate
23	2.2	Moderate
24	2.2	Moderate
25	2.1	Moderate
26	2.1	Moderate
27	2.0	Moderate
28	2.0	Moderate
29	1.9	Dim
30	1.9	Dim

Planning a trip in September

Is September a good time to visit Isle of Lewis?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

3.7

Sightseeing

3rd-best month of the year

—

Beach & pool

never really warm enough

September is a weaker month for outdoor sightseeing in Isle of Lewis.

What to pack for Isle of Lewis in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Isle of Lewis sees daytime highs around 15°C and nights near 10°C. Pack rain gear. Worth having: a warm layer. About 16 days see rain.

rain geara warm layer

Sea temperature near Isle of Lewis in September

The nearest coast averages about 13°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea offshore is warmest in August at about 13°C and coldest in March near 8°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sea temperature (°C)	9	8	8	8	9	11	13	13	13	12	11	10
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	9	Bracing
Feb	8	Bracing
Mar	8	Bracing
Apr	8	Bracing
May	9	Bracing
Jun	11	Bracing
Jul	13	Bracing
Aug	13	Bracing
Sep	13	Bracing
Oct	12	Bracing
Nov	11	Bracing
Dec	10	Bracing

UV index in Isle of Lewis in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Isle of Lewis peaks around July 12 at about 5 (high) — a little sun protection helps at midday. It bottoms out near December 19 at about 0 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 4 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	0	1	2	3	4	5	5	4	2	1	0	0
Level	Low	Low	Low	Moderate	Moderate	Moderate	High	Moderate	Moderate	Low	Low	Low

	UV index (midday)	Level
Jan	0	Low
Feb	1	Low
Mar	2	Low
Apr	3	Moderate
May	4	Moderate
Jun	5	Moderate
Jul	5	High
Aug	4	Moderate
Sep	2	Moderate
Oct	1	Low
Nov	0	Low
Dec	0	Low

Location & terrain

Where is Isle of Lewis?

Isle of Lewis sits at 58.2°N, 6.4°W, 14 m above sea level, in United Kingdom. The nearest listed city is Inverness, 152 km away.

Topography around Isle of Lewis

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Isle of Lewis.

Within 3 km, the terrain around Isle of Lewis has only modest variations in elevation — a maximum elevation change of 101 m around an average of 30 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 287 m; within 80 km, large variations in elevation — a maximum elevation change of 1,019 m.

The land around Isle of Lewis is covered by grassland (68%) within 3 km, grassland (60%) and water (37%) within 16 km, and water (77%) and grassland (22%) within 80 km.

3 km

101 m

grassland 68%

16 km

287 m

grassland 60%

80 km

1,019 m

water 77%

treesgrasslandartificial surfacesbare terrainwaterwetland

← August Isle of Lewis year-round climate October →Best places to visit in September

September weather nearby: Inverness 152 km · Fort William 174 km · Elgin 192 km · Perth 270 km · Greenock 271 km · Vale of Leven 273 km · Dumbarton 276 km · Stirling 276 km

United Kingdom travel facts

Travel advisory: Level 2; Exercise Increased Caution
Power plugs: Type D / G / M; 230 V · 50 Hz
Prices: ≈ 89% of US; price level, 2025
GDP per capita: $57,602; 2025
Happiness: 6.7 / 10; World Happiness, 2025
Safe drinking water: 100%; of population, 2024
Homicide rate: 1.1; per 100k, 2021
Road deaths: 3.2; 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 Isle of Lewis (58.219°, -6.388°, elevation 14 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).

	Avg high (°C)	Avg low (°C)
1	16	11
2	16	11
3	16	11
4	16	11
5	16	11
6	16	11
7	16	11
8	16	11
9	16	11
10	16	10
11	15	10
12	15	10
13	15	10
14	15	10
15	15	10
16	15	10
17	15	10
18	15	10
19	15	10
20	15	10
21	15	10
22	15	10
23	15	10
24	14	9
25	14	9
26	14	9
27	14	9
28	14	9
29	14	9
30	14	9

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	16	84
8	16	84
9	16	84
10	16	84
11	18	82
12	18	82
13	18	82
14	19	81
15	19	81
16	19	81
17	19	81
18	21	79
19	21	79
20	21	79
21	20	80
22	20	80
23	20	80
24	21	79
25	21	79
26	21	79
27	21	79
28	21	79
29	21	79
30	21	79

	Rain chance (%)
1	55
2	54
3	55
4	55
5	55
6	55
7	55
8	55
9	54
10	54
11	54
12	53
13	53
14	53
15	53
16	52
17	52
18	52
19	51
20	51
21	50
22	50
23	51
24	51
25	52
26	53
27	53
28	54
29	55
30	56

	Dry (%)	Comfortable (%)
1	89	11
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	90	10
8	91	9
9	91	9
10	92	8
11	92	8
12	93	7
13	93	7
14	93	7
15	94	6
16	94	6
17	94	6
18	94	6
19	95	5
20	95	5
21	95	5
22	95	5
23	95	5
24	95	5
25	95	5
26	96	4
27	96	4
28	96	4
29	96	4
30	96	4

	Avg high (°C)	Avg low (°C)
1	16	11
2	16	11
3	16	11
4	16	11
5	16	11
6	16	11
7	16	11
8	16	11
9	16	11
10	16	10
11	15	10
12	15	10
13	15	10
14	15	10
15	15	10
16	15	10
17	15	10
18	15	10
19	15	10
20	15	10
21	15	10
22	15	10
23	15	10
24	14	9
25	14	9
26	14	9
27	14	9
28	14	9
29	14	9
30	14	9

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	16	84
8	16	84
9	16	84
10	16	84
11	18	82
12	18	82
13	18	82
14	19	81
15	19	81
16	19	81
17	19	81
18	21	79
19	21	79
20	21	79
21	20	80
22	20	80
23	20	80
24	21	79
25	21	79
26	21	79
27	21	79
28	21	79
29	21	79
30	21	79

	Rain chance (%)
1	55
2	54
3	55
4	55
5	55
6	55
7	55
8	55
9	54
10	54
11	54
12	53
13	53
14	53
15	53
16	52
17	52
18	52
19	51
20	51
21	50
22	50
23	51
24	51
25	52
26	53
27	53
28	54
29	55
30	56

	Dry (%)	Comfortable (%)
1	89	11
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	90	10
8	91	9
9	91	9
10	92	8
11	92	8
12	93	7
13	93	7
14	93	7
15	94	6
16	94	6
17	94	6
18	94	6
19	95	5
20	95	5
21	95	5
22	95	5
23	95	5
24	95	5
25	95	5
26	96	4
27	96	4
28	96	4
29	96	4
30	96	4

	Avg high (°C)	Avg low (°C)
1	16	11
2	16	11
3	16	11
4	16	11
5	16	11
6	16	11
7	16	11
8	16	11
9	16	11
10	16	10
11	15	10
12	15	10
13	15	10
14	15	10
15	15	10
16	15	10
17	15	10
18	15	10
19	15	10
20	15	10
21	15	10
22	15	10
23	15	10
24	14	9
25	14	9
26	14	9
27	14	9
28	14	9
29	14	9
30	14	9

	Clearer (%)	Cloudier (%)
1	17	83
2	17	83
3	17	83
4	17	83
5	17	83
6	17	83
7	16	84
8	16	84
9	16	84
10	16	84
11	18	82
12	18	82
13	18	82
14	19	81
15	19	81
16	19	81
17	19	81
18	21	79
19	21	79
20	21	79
21	20	80
22	20	80
23	20	80
24	21	79
25	21	79
26	21	79
27	21	79
28	21	79
29	21	79
30	21	79

	Rain chance (%)
1	55
2	54
3	55
4	55
5	55
6	55
7	55
8	55
9	54
10	54
11	54
12	53
13	53
14	53
15	53
16	52
17	52
18	52
19	51
20	51
21	50
22	50
23	51
24	51
25	52
26	53
27	53
28	54
29	55
30	56

	Dry (%)	Comfortable (%)
1	89	11
2	90	10
3	90	10
4	90	10
5	90	10
6	90	10
7	90	10
8	91	9
9	91	9
10	92	8
11	92	8
12	93	7
13	93	7
14	93	7
15	94	6
16	94	6
17	94	6
18	94	6
19	95	5
20	95	5
21	95	5
22	95	5
23	95	5
24	95	5
25	95	5
26	96	4
27	96	4
28	96	4
29	96	4
30	96	4