Solothurn weather in September

In September, Solothurn sees average daytime highs of 19°C and overnight lows near 10°C, with 108 mm of rain across 13.6 wet days and about 12.4 hours of daylight. It is the 4th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 20°C in the first days to 17°C by the end. The sky is clear or mostly clear about 25% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 12 min at the start of September to 11 h 30 min by month's end. Set against the rest of the year, September is Solothurn's 3rd-clearest and 9th-windiest month. For the whole year in context, see Solothurn's year-round climate.

Daytime high: 19°; 4th warmest
Overnight low: 10°; 9th coldest
Rainfall: 108 mm; 13.6 wet days
Daylight: 12 h 18 min; 6:14 AM – 6:34 PM
Cloud cover: 63%; 3rd clearest
Wind: 6 km/h; 9th windiest
Solar energy: 3.57 kWh/m²
Travel score: 5.3; out of 10

Air quality: Good; PM2.5 9 µg/m³ · 2020

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

← August Solothurn 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 20°C in the first days to 17°C by the end.

A typical September day in Solothurn reaches about 19°C in the afternoon and slips back to 10°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 24°C. Set against its neighbours, September runs about 4°C cooler than August and about 5°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)	21	21	20	20	20	20	20	20	19	19	19	19	19	19	19	18	18	18	18	18	18	18	17	17	17	17	17	17	16	16
Avg low (°C)	12	12	11	11	11	11	11	11	11	11	10	10	10	10	10	10	10	10	9	9	9	9	9	9	9	9	9	9	8	8

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

How September really feels in Solothurn

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.

Solothurn weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 5th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	4° / -2°	83	13	7.1	8.7	0.0
Feb	5° / -2°	74	11.7	6.7	10	0.2
Mar	10° / 2°	90	14.1	4.9	11.6	2.0
Apr	14° / 5°	103	15.6	2.2	13.3	3.4
May	18° / 9°	146	17.9	0.2	14.8	4.6
Jun	21° / 12°	140	17.5	0	15.6	5.4
Jul	23° / 14°	146	17.1	0	15.3	5.9
Aug	23° / 13°	149	16.3	0	14	5.9
Sep	19° / 10°	108	13.6	0	12.4	5.3
Oct	14° / 6°	102	13.4	0.4	10.6	3.5
Nov	8° / 2°	96	13.3	3.6	9.1	1.0
Dec	4° / -1°	100	14.2	6.4	8.4	0.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 25% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 60%. Skies tend to cloud over as the month goes on.

	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 (%)	47	47	46	46	45	45	45	44	44	44	41	41	41	40	40	39	39	38	37	37	37	36	36	36	35	34	34	33	32	31
Cloudier (%)	53	53	54	54	55	55	55	56	56	56	59	59	59	60	60	61	61	62	63	63	63	64	64	64	65	66	66	67	68	69

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	46	54
4	46	54
5	45	55
6	45	55
7	45	55
8	44	56
9	44	56
10	44	56
11	41	59
12	41	59
13	41	59
14	40	60
15	40	60
16	39	61
17	39	61
18	38	62
19	37	63
20	37	63
21	37	63
22	36	64
23	36	64
24	36	64
25	35	65
26	34	66
27	34	66
28	33	67
29	32	68
30	31	69

Chance of precipitation in September

Any precipitation

Solothurn gets around 108 mm of rain over 13.6 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 46% and peaks near 49% 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 (%)	49	48	48	48	48	48	48	48	48	47	47	47	46	46	46	45	45	45	45	44	44	44	44	44	44	45	45	46	47	47

	Rain chance (%)
1	49
2	48
3	48
4	48
5	48
6	48
7	48
8	48
9	48
10	47
11	47
12	47
13	46
14	46
15	46
16	45
17	45
18	45
19	45
20	44
21	44
22	44
23	44
24	44
25	44
26	45
27	45
28	46
29	47
30	47

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 77% 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 (%)	61	62	64	65	66	67	69	69	71	71	73	73	74	75	76	77	78	79	80	81	83	84	85	86	87	88	89	90	91	92
Comfortable (%)	31	31	30	30	29	29	28	28	27	27	26	26	25	24	24	23	22	21	20	19	17	16	15	14	13	12	11	10	9	8
Humid (%)	8	7	6	5	5	4	3	3	2	2	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)
1	61	31	8
2	62	31	7
3	64	30	6
4	65	30	5
5	66	29	5
6	67	29	4
7	69	28	3
8	69	28	3
9	71	27	2
10	71	27	2
11	73	26	1
12	73	26	1
13	74	25	1
14	75	24	1
15	76	24	0
16	77	23	0
17	78	22	0
18	79	21	0
19	80	20	0
20	81	19	0
21	83	17	0
22	84	16	0
23	85	15	0
24	86	14	0
25	87	13	0
26	88	12	0
27	89	11	0
28	90	10	0
29	91	9	0
30	92	8	0

Wind in September

Winds average 6 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 7 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)	6	6	6	6	7	7	7	7	7	7	7	7	7	7	7	7	7	7	6	6	6	6	6	6	6	6	6	6	6	6
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	6	calm
2	6	calm
3	6	calm
4	6	calm
5	7	calm
6	7	calm
7	7	calm
8	7	calm
9	7	calm
10	7	calm
11	7	calm
12	7	calm
13	7	calm
14	7	calm
15	7	calm
16	7	calm
17	7	calm
18	7	calm
19	6	calm
20	6	calm
21	6	calm
22	6	calm
23	6	calm
24	6	calm
25	6	calm
26	6	calm
27	6	calm
28	6	calm
29	6	calm
30	6	calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 12 min at the start of September to 11 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 102 minutes over September. Sunrise moves from 5:54 AM to 6:34 AM, and sunset from 7:05 PM to 6:05 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)	13.2	13.1	13.1	13.0	13.0	12.9	12.9	12.8	12.7	12.7	12.6	12.6	12.5	12.4	12.4	12.3	12.3	12.2	12.2	12.1	12.0	12.0	11.9	11.9	11.8	11.8	11.7	11.6	11.6	11.5
Sunrise (AM)	5:54	5:55	5:56	5:58	5:59	6:01	6:02	6:03	6:05	6:06	6:07	6:09	6:10	6:11	6:13	6:14	6:16	6:17	6:18	6:20	6:21	6:22	6:24	6:25	6:27	6:28	6:29	6:31	6:32	6:34
Sunset (PM)	7:05	7:03	7:01	6:59	6:57	6:55	6:53	6:51	6:49	6:47	6:45	6:43	6:41	6:38	6:36	6:34	6:32	6:30	6:28	6:26	6:24	6:22	6:19	6:17	6:15	6:13	6:11	6:09	6:07	6:05

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	5:54	7:05
2	13.1	5:55	7:03
3	13.1	5:56	7:01
4	13.0	5:58	6:59
5	13.0	5:59	6:57
6	12.9	6:01	6:55
7	12.9	6:02	6:53
8	12.8	6:03	6:51
9	12.7	6:05	6:49
10	12.7	6:06	6:47
11	12.6	6:07	6:45
12	12.6	6:09	6:43
13	12.5	6:10	6:41
14	12.4	6:11	6:38
15	12.4	6:13	6:36
16	12.3	6:14	6:34
17	12.3	6:16	6:32
18	12.2	6:17	6:30
19	12.2	6:18	6:28
20	12.1	6:20	6:26
21	12.0	6:21	6:24
22	12.0	6:22	6:22
23	11.9	6:24	6:19
24	11.9	6:25	6:17
25	11.8	6:27	6:15
26	11.8	6:28	6:13
27	11.7	6:29	6:11
28	11.6	6:31	6:09
29	11.6	6:32	6:07
30	11.5	6:34	6:05

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.57 kWh/m².

For context, solar energy here swings from a low near 1.03 kWh/m² to a high of 5.59 kWh/m² in July across the year — September's 3.57 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)	4.2	4.2	4.1	4.1	4.0	4.0	4.0	3.9	3.9	3.8	3.8	3.7	3.7	3.6	3.6	3.5	3.5	3.5	3.4	3.4	3.3	3.3	3.2	3.2	3.1	3.1	3.0	3.0	2.9	2.9
Level	Bright	Bright	Bright	Bright	Bright	Bright	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	4.2	Bright
2	4.2	Bright
3	4.1	Bright
4	4.1	Bright
5	4.0	Bright
6	4.0	Bright
7	4.0	Moderate
8	3.9	Moderate
9	3.9	Moderate
10	3.8	Moderate
11	3.8	Moderate
12	3.7	Moderate
13	3.7	Moderate
14	3.6	Moderate
15	3.6	Moderate
16	3.5	Moderate
17	3.5	Moderate
18	3.5	Moderate
19	3.4	Moderate
20	3.4	Moderate
21	3.3	Moderate
22	3.3	Moderate
23	3.2	Moderate
24	3.2	Moderate
25	3.1	Moderate
26	3.1	Moderate
27	3.0	Moderate
28	3.0	Moderate
29	2.9	Moderate
30	2.9	Moderate

Planning a trip in September

Is September a good time to visit Solothurn?

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

5.3

Sightseeing

4th-best month of the year

2.1

Beach & pool

4th-best month of the year

September is a reasonable time to visit Solothurn for sightseeing.

What to pack for Solothurn in September

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

In September, Solothurn sees daytime highs around 19°C and nights near 10°C. Pack rain gear. About 14 days see rain.

rain gear

UV index in Solothurn in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 4 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Solothurn peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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	7	8	7	4	3	2	1
Level	Low	Low	Moderate	Moderate	High	Very high	Very high	High	Moderate	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Low
Mar	4	Moderate
Apr	5	Moderate
May	7	High
Jun	7	Very high
Jul	8	Very high
Aug	7	High
Sep	4	Moderate
Oct	3	Moderate
Nov	2	Low
Dec	1	Low

Location & terrain

Where is Solothurn?

Solothurn sits at 47.2°N, 7.5°E, 440 m above sea level, in Switzerland. The nearest listed city is Grenchen, 11 km away.

Topography around Solothurn

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

Within 3 km, the terrain around Solothurn has only modest variations in elevation — a maximum elevation change of 182 m around an average of 471 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,021 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,836 m.

The land around Solothurn is covered by trees (41%) and artificial surfaces (24%) within 3 km, trees (47%), grassland (24%) and cropland (21%) within 16 km, and trees (47%) and grassland (31%) within 80 km.

3 km

182 m

trees 41%

16 km

1,021 m

trees 47%

80 km

3,836 m

trees 47%

treesgrasslandcroplandartificial surfacesbare terrainwater

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

September weather nearby: Grenchen 11 km · Burgdorf 18 km · Biel/Bienne 23 km · Bern 30 km · Olten 32 km · Reinach 32 km · Köniz 33 km · Muttenz 36 km

Switzerland travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type C / J; 230 V · 50 Hz
Prices: ≈ 112% of US; price level, 2025
GDP per capita: $114,769; 2025
Happiness: 7.0 / 10; World Happiness, 2025
Safe drinking water: 97%; of population, 2024
Homicide rate: 0.6; per 100k, 2023
Road deaths: 2.2; per 100k/yr, 2019
Income group: High; World Bank
English: High; EF EPI 564
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 Solothurn (47.2079°, 7.5371°, elevation 440 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	21	12
2	21	12
3	20	11
4	20	11
5	20	11
6	20	11
7	20	11
8	20	11
9	19	11
10	19	11
11	19	10
12	19	10
13	19	10
14	19	10
15	19	10
16	18	10
17	18	10
18	18	10
19	18	9
20	18	9
21	18	9
22	18	9
23	17	9
24	17	9
25	17	9
26	17	9
27	17	9
28	17	9
29	16	8
30	16	8

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	46	54
4	46	54
5	45	55
6	45	55
7	45	55
8	44	56
9	44	56
10	44	56
11	41	59
12	41	59
13	41	59
14	40	60
15	40	60
16	39	61
17	39	61
18	38	62
19	37	63
20	37	63
21	37	63
22	36	64
23	36	64
24	36	64
25	35	65
26	34	66
27	34	66
28	33	67
29	32	68
30	31	69

	Rain chance (%)
1	49
2	48
3	48
4	48
5	48
6	48
7	48
8	48
9	48
10	47
11	47
12	47
13	46
14	46
15	46
16	45
17	45
18	45
19	45
20	44
21	44
22	44
23	44
24	44
25	44
26	45
27	45
28	46
29	47
30	47

	Dry (%)	Comfortable (%)	Humid (%)
1	61	31	8
2	62	31	7
3	64	30	6
4	65	30	5
5	66	29	5
6	67	29	4
7	69	28	3
8	69	28	3
9	71	27	2
10	71	27	2
11	73	26	1
12	73	26	1
13	74	25	1
14	75	24	1
15	76	24	0
16	77	23	0
17	78	22	0
18	79	21	0
19	80	20	0
20	81	19	0
21	83	17	0
22	84	16	0
23	85	15	0
24	86	14	0
25	87	13	0
26	88	12	0
27	89	11	0
28	90	10	0
29	91	9	0
30	92	8	0

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

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	46	54
4	46	54
5	45	55
6	45	55
7	45	55
8	44	56
9	44	56
10	44	56
11	41	59
12	41	59
13	41	59
14	40	60
15	40	60
16	39	61
17	39	61
18	38	62
19	37	63
20	37	63
21	37	63
22	36	64
23	36	64
24	36	64
25	35	65
26	34	66
27	34	66
28	33	67
29	32	68
30	31	69

	Rain chance (%)
1	49
2	48
3	48
4	48
5	48
6	48
7	48
8	48
9	48
10	47
11	47
12	47
13	46
14	46
15	46
16	45
17	45
18	45
19	45
20	44
21	44
22	44
23	44
24	44
25	44
26	45
27	45
28	46
29	47
30	47

	Dry (%)	Comfortable (%)	Humid (%)
1	61	31	8
2	62	31	7
3	64	30	6
4	65	30	5
5	66	29	5
6	67	29	4
7	69	28	3
8	69	28	3
9	71	27	2
10	71	27	2
11	73	26	1
12	73	26	1
13	74	25	1
14	75	24	1
15	76	24	0
16	77	23	0
17	78	22	0
18	79	21	0
19	80	20	0
20	81	19	0
21	83	17	0
22	84	16	0
23	85	15	0
24	86	14	0
25	87	13	0
26	88	12	0
27	89	11	0
28	90	10	0
29	91	9	0
30	92	8	0

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

	Clearer (%)	Cloudier (%)
1	47	53
2	47	53
3	46	54
4	46	54
5	45	55
6	45	55
7	45	55
8	44	56
9	44	56
10	44	56
11	41	59
12	41	59
13	41	59
14	40	60
15	40	60
16	39	61
17	39	61
18	38	62
19	37	63
20	37	63
21	37	63
22	36	64
23	36	64
24	36	64
25	35	65
26	34	66
27	34	66
28	33	67
29	32	68
30	31	69

	Rain chance (%)
1	49
2	48
3	48
4	48
5	48
6	48
7	48
8	48
9	48
10	47
11	47
12	47
13	46
14	46
15	46
16	45
17	45
18	45
19	45
20	44
21	44
22	44
23	44
24	44
25	44
26	45
27	45
28	46
29	47
30	47

	Dry (%)	Comfortable (%)	Humid (%)
1	61	31	8
2	62	31	7
3	64	30	6
4	65	30	5
5	66	29	5
6	67	29	4
7	69	28	3
8	69	28	3
9	71	27	2
10	71	27	2
11	73	26	1
12	73	26	1
13	74	25	1
14	75	24	1
15	76	24	0
16	77	23	0
17	78	22	0
18	79	21	0
19	80	20	0
20	81	19	0
21	83	17	0
22	84	16	0
23	85	15	0
24	86	14	0
25	87	13	0
26	88	12	0
27	89	11	0
28	90	10	0
29	91	9	0
30	92	8	0