Longyearbyen weather in September

In September, Longyearbyen sees average daytime highs of 1°C and overnight lows near -1°C, with 45 mm of precipitation across 9.8 wet days and about 13.7 hours of daylight. It is the 4th-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 3°C in the first days to -1°C by the end. The sky is clear or mostly clear about 3% of the time in September, and the air most often feels dry.

Daylight stretches from about 17 h 48 min at the start of September to 9 h 48 min by month's end. Set against the rest of the year, September is Longyearbyen's 10th-clearest and 9th-windiest month. For the whole year in context, see Longyearbyen's year-round climate.

Daytime high: 1°; 4th warmest
Overnight low: -1°; 9th coldest
Precipitation: 45 mm; 9.8 wet days
Daylight: 13 h 30 min; 5:07 AM – 6:36 PM
Cloud cover: 87%; 10th clearest
Wind: 9 km/h; 9th windiest
Solar energy: 0.95 kWh/m²
Travel score: 0.0; out of 10

Longyearbyen is town and administrative centre in Svalbard, Norway.

Density: 10/km²; people per km²
Founded: 1906

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

← August Longyearbyen 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 3°C in the first days to -1°C by the end.

A typical September day in Longyearbyen reaches about 1°C in the afternoon and slips back to -1°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between -2°C and 5°C. Set against its neighbours, September runs about 4°C cooler than August and about 6°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)	4	3	3	3	3	3	3	3	2	2	2	2	2	2	2	1	1	1	1	1	1	0	0	0	0	0	0	-1	-1	-1
Avg low (°C)	1	1	1	1	0	0	0	0	0	0	0	0	-1	-1	-1	-1	-1	-1	-2	-2	-2	-2	-2	-3	-3	-3	-3	-3	-4	-4

	Avg high (°C)	Avg low (°C)
1	4	1
2	3	1
3	3	1
4	3	1
5	3	0
6	3	0
7	3	0
8	3	0
9	2	0
10	2	0
11	2	0
12	2	0
13	2	-1
14	2	-1
15	2	-1
16	1	-1
17	1	-1
18	1	-1
19	1	-2
20	1	-2
21	1	-2
22	0	-2
23	0	-2
24	0	-3
25	0	-3
26	0	-3
27	0	-3
28	-1	-3
29	-1	-4
30	-1	-4

How September really feels in Longyearbyen

Once humidity and wind are folded in, September averages 0 days that feel above 32°C and 30 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

The story in September is cold — wind chill drags the overnight "feels like" below the raw low.

Longyearbyen weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 3rd-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	-11° / -16°	43	8.9	10.9	0	0.0
Feb	-12° / -16°	31	7.1	9	1	0.0
Mar	-12° / -17°	35	8.4	10.2	10	0.0
Apr	-9° / -13°	23	6.8	8.7	19.3	0.0
May	-3° / -5°	21	6	7.7	24	0.0
Jun	2° / 1°	18	5	3.7	24	0.0
Jul	7° / 4°	32	8.2	1.1	24	0.7
Aug	5° / 3°	40	9	2.2	22.8	0.3
Sep	1° / -1°	45	9.8	5.3	13.7	0.0
Oct	-4° / -8°	41	9.1	9	4.4	0.0
Nov	-7° / -12°	47	10.3	12.2	0	0.0
Dec	-10° / -14°	45	9.7	11.9	0	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 3% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 5% of September, with mostly cloudy or overcast conditions the remaining 91%.

	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 (%)	13	13	13	13	11	11	10	10	9	9	9	9	8	8	8	8	8	8	8	8	7	7	7	7	7	7	7	7	7	7
Cloudier (%)	87	87	87	87	89	89	90	90	91	91	91	91	92	92	92	92	92	92	92	92	93	93	93	93	93	93	93	93	93	93

	Clearer (%)	Cloudier (%)
1	13	87
2	13	87
3	13	87
4	13	87
5	11	89
6	11	89
7	10	90
8	10	90
9	9	91
10	9	91
11	9	91
12	9	91
13	8	92
14	8	92
15	8	92
16	8	92
17	8	92
18	8	92
19	8	92
20	8	92
21	7	93
22	7	93
23	7	93
24	7	93
25	7	93
26	7	93
27	7	93
28	7	93
29	7	93
30	7	93

Chance of precipitation in September

Any precipitationSnow

Longyearbyen gets around 45 mm of rain and snow over 9.8 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 33% and peaks near 36% on the wettest days, and about 5 days bring snow.

	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 (%)	35	35	36	36	36	36	36	36	36	35	35	35	34	34	33	33	33	32	32	31	31	31	30	30	30	30	31	31	31	31
Snow chance (%)	12	12	13	13	13	14	14	14	15	15	16	16	16	16	17	17	17	18	18	19	20	21	22	22	23	24	24	25	26	26

	Rain chance (%)	Snow chance (%)
1	35	12
2	35	12
3	36	13
4	36	13
5	36	13
6	36	14
7	36	14
8	36	14
9	36	15
10	35	15
11	35	16
12	35	16
13	34	16
14	34	16
15	33	17
16	33	17
17	33	17
18	32	18
19	32	18
20	31	19
21	31	20
22	31	21
23	30	22
24	30	22
25	30	23
26	30	24
27	31	24
28	31	25
29	31	26
30	31	26

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 100% 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 (%)	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

Wind in September

Winds average 9 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 10 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)	9	9	9	9	9	9	9	9	9	9	9	9	9	9	10	10	10	10	10	10	10	10	9	9	9	9	9	9	9	9
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	calm	calm	calm	calm	calm	calm

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

Sunrise & sunset in September

DaylightNight

Daylight runs from about 17 h 48 min at the start of September to 9 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 480 minutes over September. Sunrise moves from 3:02 AM to 6:51 AM, and sunset from 8:52 PM to 4:42 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)	17.8	17.5	17.2	16.9	16.5	16.2	16.0	15.7	15.4	15.1	14.8	14.6	14.3	14.0	13.8	13.5	13.2	13.0	12.7	12.5	12.2	11.9	11.7	11.4	11.2	10.9	10.6	10.4	10.1	9.8
Sunrise (AM)	3:02	3:12	3:21	3:31	3:39	3:48	3:56	4:05	4:13	4:21	4:29	4:37	4:44	4:52	4:59	5:07	5:14	5:22	5:29	5:37	5:44	5:51	5:59	6:06	6:14	6:21	6:29	6:36	6:44	6:51
Sunset (PM)	8:52	8:42	8:31	8:22	8:12	8:03	7:54	7:45	7:36	7:27	7:18	7:10	7:01	6:53	6:45	6:36	6:28	6:20	6:12	6:04	5:56	5:48	5:39	5:31	5:23	5:15	5:07	4:59	4:50	4:42

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	17.8	3:02	8:52
2	17.5	3:12	8:42
3	17.2	3:21	8:31
4	16.9	3:31	8:22
5	16.5	3:39	8:12
6	16.2	3:48	8:03
7	16.0	3:56	7:54
8	15.7	4:05	7:45
9	15.4	4:13	7:36
10	15.1	4:21	7:27
11	14.8	4:29	7:18
12	14.6	4:37	7:10
13	14.3	4:44	7:01
14	14.0	4:52	6:53
15	13.8	4:59	6:45
16	13.5	5:07	6:36
17	13.2	5:14	6:28
18	13.0	5:22	6:20
19	12.7	5:29	6:12
20	12.5	5:37	6:04
21	12.2	5:44	5:56
22	11.9	5:51	5:48
23	11.7	5:59	5:39
24	11.4	6:06	5:31
25	11.2	6:14	5:23
26	10.9	6:21	5:15
27	10.6	6:29	5:07
28	10.4	6:36	4:59
29	10.1	6:44	4:50
30	9.8	6:51	4:42

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 0.95 kWh/m².

For context, solar energy here swings from a low near 0 kWh/m² to a high of 5.97 kWh/m² in June across the year — September's 0.95 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)	1.6	1.6	1.5	1.4	1.4	1.4	1.3	1.3	1.2	1.2	1.1	1.1	1.0	1.0	1.0	0.9	0.9	0.8	0.8	0.8	0.7	0.7	0.7	0.6	0.6	0.6	0.5	0.5	0.5	0.4
Level	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim	Dim

	Solar energy (kWh/m²)	Level
1	1.6	Dim
2	1.6	Dim
3	1.5	Dim
4	1.4	Dim
5	1.4	Dim
6	1.4	Dim
7	1.3	Dim
8	1.3	Dim
9	1.2	Dim
10	1.2	Dim
11	1.1	Dim
12	1.1	Dim
13	1.0	Dim
14	1.0	Dim
15	1.0	Dim
16	0.9	Dim
17	0.9	Dim
18	0.8	Dim
19	0.8	Dim
20	0.8	Dim
21	0.7	Dim
22	0.7	Dim
23	0.7	Dim
24	0.6	Dim
25	0.6	Dim
26	0.6	Dim
27	0.5	Dim
28	0.5	Dim
29	0.5	Dim
30	0.4	Dim

Planning a trip in September

Is September a good time to visit Longyearbyen?

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

0.0

Sightseeing

3rd-best month of the year

—

Beach & pool

never really warm enough

September is a weaker month for outdoor sightseeing in Longyearbyen.

What to pack for Longyearbyen in September

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

In September, Longyearbyen sees daytime highs around 1°C and nights near -1°C. Pack a warm layer and a heavy coat. Worth having: rain gear. About 10 days see rain.

a warm layera heavy coatrain gear

UV index in Longyearbyen in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 0. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Longyearbyen peaks around June 18 at about 2 (moderate) — sun protection is rarely needed. It bottoms out near January 1 at about 0 (low).

The midday index never reaches 3, the level where the WHO starts recommending sun protection.

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

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

Location & terrain

Where is Longyearbyen?

Longyearbyen sits at 78.2°N, 15.6°E, 1 m above sea level, in Svalbard and Jan Mayen. The nearest listed city is Alta, 945 km away.

Topography around Longyearbyen

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

Within 3 km, the terrain around Longyearbyen has significant variations in elevation — a maximum elevation change of 485 m around an average of 113 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,061 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,255 m.

The land around Longyearbyen is covered by water (35%), bare terrain (30%) and moss and lichen (27%) within 3 km, bare terrain (31%), water (29%) and moss and lichen (22%) within 16 km, and snow and ice (30%), water (29%) and bare terrain (26%) within 80 km.

3 km

485 m

water 35%

16 km

1,061 m

bare terrain 31%

80 km

1,255 m

snow and ice 30%

grasslandartificial surfacesbare terrainsnow and icewaterwetlandmoss and lichen

← August Longyearbyen year-round climate October →Best places to visit in September

September weather nearby: Alta 945 km · Tromso 958 km · Tromsdalen 959 km · Harstad 1,048 km · Nikel 1,071 km · Zapolyarnyy 1,077 km · Lofoten 1,111 km · Polyarnyy 1,135 km

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Longyearbyen (78.2233°, 15.6469°, elevation 1 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. 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	4	1
2	3	1
3	3	1
4	3	1
5	3	0
6	3	0
7	3	0
8	3	0
9	2	0
10	2	0
11	2	0
12	2	0
13	2	-1
14	2	-1
15	2	-1
16	1	-1
17	1	-1
18	1	-1
19	1	-2
20	1	-2
21	1	-2
22	0	-2
23	0	-2
24	0	-3
25	0	-3
26	0	-3
27	0	-3
28	-1	-3
29	-1	-4
30	-1	-4

	Clearer (%)	Cloudier (%)
1	13	87
2	13	87
3	13	87
4	13	87
5	11	89
6	11	89
7	10	90
8	10	90
9	9	91
10	9	91
11	9	91
12	9	91
13	8	92
14	8	92
15	8	92
16	8	92
17	8	92
18	8	92
19	8	92
20	8	92
21	7	93
22	7	93
23	7	93
24	7	93
25	7	93
26	7	93
27	7	93
28	7	93
29	7	93
30	7	93

	Rain chance (%)	Snow chance (%)
1	35	12
2	35	12
3	36	13
4	36	13
5	36	13
6	36	14
7	36	14
8	36	14
9	36	15
10	35	15
11	35	16
12	35	16
13	34	16
14	34	16
15	33	17
16	33	17
17	33	17
18	32	18
19	32	18
20	31	19
21	31	20
22	31	21
23	30	22
24	30	22
25	30	23
26	30	24
27	31	24
28	31	25
29	31	26
30	31	26

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Solar energy (kWh/m²)	Level
1	1.6	Dim
2	1.6	Dim
3	1.5	Dim
4	1.4	Dim
5	1.4	Dim
6	1.4	Dim
7	1.3	Dim
8	1.3	Dim
9	1.2	Dim
10	1.2	Dim
11	1.1	Dim
12	1.1	Dim
13	1.0	Dim
14	1.0	Dim
15	1.0	Dim
16	0.9	Dim
17	0.9	Dim
18	0.8	Dim
19	0.8	Dim
20	0.8	Dim
21	0.7	Dim
22	0.7	Dim
23	0.7	Dim
24	0.6	Dim
25	0.6	Dim
26	0.6	Dim
27	0.5	Dim
28	0.5	Dim
29	0.5	Dim
30	0.4	Dim

	Avg high (°C)	Avg low (°C)
1	4	1
2	3	1
3	3	1
4	3	1
5	3	0
6	3	0
7	3	0
8	3	0
9	2	0
10	2	0
11	2	0
12	2	0
13	2	-1
14	2	-1
15	2	-1
16	1	-1
17	1	-1
18	1	-1
19	1	-2
20	1	-2
21	1	-2
22	0	-2
23	0	-2
24	0	-3
25	0	-3
26	0	-3
27	0	-3
28	-1	-3
29	-1	-4
30	-1	-4

	Clearer (%)	Cloudier (%)
1	13	87
2	13	87
3	13	87
4	13	87
5	11	89
6	11	89
7	10	90
8	10	90
9	9	91
10	9	91
11	9	91
12	9	91
13	8	92
14	8	92
15	8	92
16	8	92
17	8	92
18	8	92
19	8	92
20	8	92
21	7	93
22	7	93
23	7	93
24	7	93
25	7	93
26	7	93
27	7	93
28	7	93
29	7	93
30	7	93

	Rain chance (%)	Snow chance (%)
1	35	12
2	35	12
3	36	13
4	36	13
5	36	13
6	36	14
7	36	14
8	36	14
9	36	15
10	35	15
11	35	16
12	35	16
13	34	16
14	34	16
15	33	17
16	33	17
17	33	17
18	32	18
19	32	18
20	31	19
21	31	20
22	31	21
23	30	22
24	30	22
25	30	23
26	30	24
27	31	24
28	31	25
29	31	26
30	31	26

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Solar energy (kWh/m²)	Level
1	1.6	Dim
2	1.6	Dim
3	1.5	Dim
4	1.4	Dim
5	1.4	Dim
6	1.4	Dim
7	1.3	Dim
8	1.3	Dim
9	1.2	Dim
10	1.2	Dim
11	1.1	Dim
12	1.1	Dim
13	1.0	Dim
14	1.0	Dim
15	1.0	Dim
16	0.9	Dim
17	0.9	Dim
18	0.8	Dim
19	0.8	Dim
20	0.8	Dim
21	0.7	Dim
22	0.7	Dim
23	0.7	Dim
24	0.6	Dim
25	0.6	Dim
26	0.6	Dim
27	0.5	Dim
28	0.5	Dim
29	0.5	Dim
30	0.4	Dim

	Avg high (°C)	Avg low (°C)
1	4	1
2	3	1
3	3	1
4	3	1
5	3	0
6	3	0
7	3	0
8	3	0
9	2	0
10	2	0
11	2	0
12	2	0
13	2	-1
14	2	-1
15	2	-1
16	1	-1
17	1	-1
18	1	-1
19	1	-2
20	1	-2
21	1	-2
22	0	-2
23	0	-2
24	0	-3
25	0	-3
26	0	-3
27	0	-3
28	-1	-3
29	-1	-4
30	-1	-4

	Clearer (%)	Cloudier (%)
1	13	87
2	13	87
3	13	87
4	13	87
5	11	89
6	11	89
7	10	90
8	10	90
9	9	91
10	9	91
11	9	91
12	9	91
13	8	92
14	8	92
15	8	92
16	8	92
17	8	92
18	8	92
19	8	92
20	8	92
21	7	93
22	7	93
23	7	93
24	7	93
25	7	93
26	7	93
27	7	93
28	7	93
29	7	93
30	7	93

	Rain chance (%)	Snow chance (%)
1	35	12
2	35	12
3	36	13
4	36	13
5	36	13
6	36	14
7	36	14
8	36	14
9	36	15
10	35	15
11	35	16
12	35	16
13	34	16
14	34	16
15	33	17
16	33	17
17	33	17
18	32	18
19	32	18
20	31	19
21	31	20
22	31	21
23	30	22
24	30	22
25	30	23
26	30	24
27	31	24
28	31	25
29	31	26
30	31	26

	Dry (%)
1	100
2	100
3	100
4	100
5	100
6	100
7	100
8	100
9	100
10	100
11	100
12	100
13	100
14	100
15	100
16	100
17	100
18	100
19	100
20	100
21	100
22	100
23	100
24	100
25	100
26	100
27	100
28	100
29	100
30	100

	Solar energy (kWh/m²)	Level
1	1.6	Dim
2	1.6	Dim
3	1.5	Dim
4	1.4	Dim
5	1.4	Dim
6	1.4	Dim
7	1.3	Dim
8	1.3	Dim
9	1.2	Dim
10	1.2	Dim
11	1.1	Dim
12	1.1	Dim
13	1.0	Dim
14	1.0	Dim
15	1.0	Dim
16	0.9	Dim
17	0.9	Dim
18	0.8	Dim
19	0.8	Dim
20	0.8	Dim
21	0.7	Dim
22	0.7	Dim
23	0.7	Dim
24	0.6	Dim
25	0.6	Dim
26	0.6	Dim
27	0.5	Dim
28	0.5	Dim
29	0.5	Dim
30	0.4	Dim