Lancy weather in September

In September, Lancy sees average daytime highs of 19°C and overnight lows near 10°C, with 121 mm of rain across 12 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 21°C in the first days to 17°C by the end. The sky is clear or mostly clear about 29% 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 Lancy's 4th-clearest and 11th-windiest month. For the whole year in context, see Lancy's year-round climate.

Daytime high: 19°; 4th warmest
Overnight low: 10°; 9th coldest
Rainfall: 121 mm; 12 wet days
Daylight: 12 h 18 min; 6:20 AM – 6:40 PM
Cloud cover: 59%; 4th clearest
Wind: 6 km/h; 11th windiest
Solar energy: 3.83 kWh/m²
Travel score: 5.7; out of 10

Lancy is Switzerland.

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

← August Lancy 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 21°C in the first days to 17°C by the end.

A typical September day in Lancy 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 14°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	21	21	20	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
Avg low (°C)	12	12	11	11	11	11	11	11	11	11	10	10	10	10	10	10	10	10	10	10	9	9	9	9	9	9	9	9	9	9

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

How September really feels in Lancy

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.

Lancy weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	5° / -2°	126	12.8	7.3	8.8	0.0
Feb	6° / -1°	107	11.2	6.6	10	0.4
Mar	10° / 2°	119	12.5	4.4	11.6	2.4
Apr	14° / 5°	115	13.4	2.2	13.3	3.7
May	18° / 9°	142	15.9	0.3	14.7	4.9
Jun	21° / 12°	130	14.4	0	15.5	5.9
Jul	24° / 14°	131	13.5	0	15.2	6.6
Aug	23° / 13°	129	13.2	0	14	6.6
Sep	19° / 10°	121	12	0	12.3	5.7
Oct	14° / 6°	128	12.9	0.5	10.7	3.9
Nov	9° / 2°	136	13.2	3.6	9.2	1.4
Dec	5° / -1°	147	13.5	6.8	8.5	0.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 29% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 17% of September, with mostly cloudy or overcast conditions the remaining 54%. 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 (%)	54	54	53	53	53	53	53	52	52	51	51	50	49	49	48	47	46	45	43	43	42	42	41	40	40	39	39	37	37	36
Cloudier (%)	46	46	47	47	47	47	47	48	48	49	49	50	51	51	52	53	54	55	57	57	58	58	59	60	60	61	61	63	63	64

	Clearer (%)	Cloudier (%)
1	54	46
2	54	46
3	53	47
4	53	47
5	53	47
6	53	47
7	53	47
8	52	48
9	52	48
10	51	49
11	51	49
12	50	50
13	49	51
14	49	51
15	48	52
16	47	53
17	46	54
18	45	55
19	43	57
20	43	57
21	42	58
22	42	58
23	41	59
24	40	60
25	40	60
26	39	61
27	39	61
28	37	63
29	37	63
30	36	64

Chance of precipitation in September

Any precipitation

Lancy gets around 121 mm of rain over 12 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 41% and peaks near 45% on the wettest days. The odds climb toward the end of the month.

	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 (%)	38	38	38	38	38	38	38	38	38	39	39	40	40	40	41	41	41	41	42	42	42	42	43	43	43	44	44	45	45	45

	Rain chance (%)
1	38
2	38
3	38
4	38
5	38
6	38
7	38
8	38
9	38
10	39
11	39
12	40
13	40
14	40
15	41
16	41
17	41
18	41
19	42
20	42
21	42
22	42
23	43
24	43
25	43
26	44
27	44
28	45
29	45
30	45

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 75% 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 (%)	57	58	60	61	63	64	66	67	68	69	70	71	72	74	74	75	77	78	80	81	82	83	84	85	86	87	87	88	89	90
Comfortable (%)	32	32	31	31	30	30	29	29	28	28	27	27	26	25	25	24	23	22	20	19	18	17	16	15	14	13	13	12	11	10
Humid (%)	11	10	9	8	7	6	5	4	4	3	3	2	2	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)
1	57	32	11
2	58	32	10
3	60	31	9
4	61	31	8
5	63	30	7
6	64	30	6
7	66	29	5
8	67	29	4
9	68	28	4
10	69	28	3
11	70	27	3
12	71	27	2
13	72	26	2
14	74	25	1
15	74	25	1
16	75	24	1
17	77	23	0
18	78	22	0
19	80	20	0
20	81	19	0
21	82	18	0
22	83	17	0
23	84	16	0
24	85	15	0
25	86	14	0
26	87	13	0
27	87	13	0
28	88	12	0
29	89	11	0
30	90	10	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 6 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	6	6	6	6	6	6	6	6	6	6	6	6	6	6	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	6	calm
6	6	calm
7	6	calm
8	6	calm
9	6	calm
10	6	calm
11	6	calm
12	6	calm
13	6	calm
14	6	calm
15	6	calm
16	6	calm
17	6	calm
18	6	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 6:01 AM to 6:39 AM, and sunset from 7:10 PM to 6:11 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	13.0	13.0	12.9	12.9	12.8	12.8	12.7	12.7	12.6	12.5	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)	6:01	6:02	6:03	6:05	6:06	6:07	6:08	6:10	6:11	6:12	6:14	6:15	6:16	6:18	6:19	6:20	6:22	6:23	6:24	6:25	6:27	6:28	6:29	6:31	6:32	6:33	6:35	6:36	6:37	6:39
Sunset (PM)	7:10	7:08	7:06	7:04	7:02	7:00	6:58	6:56	6:54	6:52	6:50	6:48	6:46	6:44	6:42	6:40	6:37	6:35	6:33	6:31	6:29	6:27	6:25	6:23	6:21	6:19	6:17	6:15	6:13	6:11

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	13.2	6:01	7:10
2	13.1	6:02	7:08
3	13.0	6:03	7:06
4	13.0	6:05	7:04
5	12.9	6:06	7:02
6	12.9	6:07	7:00
7	12.8	6:08	6:58
8	12.8	6:10	6:56
9	12.7	6:11	6:54
10	12.7	6:12	6:52
11	12.6	6:14	6:50
12	12.5	6:15	6:48
13	12.5	6:16	6:46
14	12.4	6:18	6:44
15	12.4	6:19	6:42
16	12.3	6:20	6:40
17	12.3	6:22	6:37
18	12.2	6:23	6:35
19	12.2	6:24	6:33
20	12.1	6:25	6:31
21	12.0	6:27	6:29
22	12.0	6:28	6:27
23	11.9	6:29	6:25
24	11.9	6:31	6:23
25	11.8	6:32	6:21
26	11.8	6:33	6:19
27	11.7	6:35	6:17
28	11.6	6:36	6:15
29	11.6	6:37	6:13
30	11.5	6:39	6:11

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.83 kWh/m².

For context, solar energy here swings from a low near 1.12 kWh/m² to a high of 5.93 kWh/m² in July across the year — September's 3.83 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)	4.5	4.5	4.5	4.4	4.4	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	3.6	3.6	3.5	3.5	3.4	3.4	3.3	3.3	3.2	3.2	3.1	3.1
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate

	Solar energy (kWh/m²)	Level
1	4.5	Bright
2	4.5	Bright
3	4.5	Bright
4	4.4	Bright
5	4.4	Bright
6	4.3	Bright
7	4.3	Bright
8	4.2	Bright
9	4.2	Bright
10	4.1	Bright
11	4.1	Bright
12	4.0	Bright
13	4.0	Moderate
14	3.9	Moderate
15	3.9	Moderate
16	3.8	Moderate
17	3.8	Moderate
18	3.7	Moderate
19	3.6	Moderate
20	3.6	Moderate
21	3.5	Moderate
22	3.5	Moderate
23	3.4	Moderate
24	3.4	Moderate
25	3.3	Moderate
26	3.3	Moderate
27	3.2	Moderate
28	3.2	Moderate
29	3.1	Moderate
30	3.1	Moderate

Planning a trip in September

Is September a good time to visit Lancy?

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

5.7

Sightseeing

4th-best month of the year

2.5

Beach & pool

4th-best month of the year

September is a reasonable time to visit Lancy for sightseeing.

What to pack for Lancy in September

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

In September, Lancy sees daytime highs around 19°C and nights near 10°C. Worth packing: rain gear. About 12 days see rain.

rain gear

UV index in Lancy in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Lancy 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	9	7	5	3	2	1
Level	Low	Moderate	Moderate	Moderate	High	Very high	Very high	High	Moderate	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Moderate
Mar	4	Moderate
Apr	5	Moderate
May	7	High
Jun	7	Very high
Jul	9	Very high
Aug	7	High
Sep	5	Moderate
Oct	3	Moderate
Nov	2	Low
Dec	1	Low

Air quality in Lancy in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Lancy is worst in April — around 15 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

Modeled monthly averages (CAMS reanalysis, 2015–2024).

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	13	12	15	15	13	15	11	11	11	10	10	11
Level	Moderate	Moderate	Moderate	Moderate	Moderate	Moderate	Good	Good	Good	Good	Good	Good

	PM2.5 (µg/m³)	Level
Jan	13	Moderate
Feb	12	Moderate
Mar	15	Moderate
Apr	15	Moderate
May	13	Moderate
Jun	15	Moderate
Jul	11	Good
Aug	11	Good
Sep	11	Good
Oct	10	Good
Nov	10	Good
Dec	11	Good

Location & terrain

Where is Lancy?

Lancy sits at 46.2°N, 6.1°E, 421 m above sea level, in Switzerland. The nearest listed city is Onex, 1.0 km away.

Topography around Lancy

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

Within 3 km, the terrain around Lancy has only modest variations in elevation — a maximum elevation change of 86 m around an average of 406 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,383 m; within 80 km, extreme variations in elevation — a maximum elevation change of 4,606 m.

The land around Lancy is covered by artificial surfaces (47%) and trees (37%) within 3 km, trees (43%) and grassland (23%) within 16 km, and trees (53%) and grassland (29%) within 80 km.

3 km

86 m

artificial surfaces 47%

16 km

1,383 m

trees 43%

80 km

4,606 m

trees 53%

treesgrasslandcroplandartificial surfacesbare terrainsnow and icewater

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

September weather nearby: Onex 1.0 km · Carouge 2.0 km · Geneva 3.0 km · Vernier 4.0 km · Meyrin 6.0 km · Annemasse 10 km · Nyon 24 km · Annecy-le-Vieux 30 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 Lancy (46.1898°, 6.1144°, elevation 421 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. 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	21	11
4	21	11
5	20	11
6	20	11
7	20	11
8	20	11
9	20	11
10	20	11
11	20	10
12	19	10
13	19	10
14	19	10
15	19	10
16	19	10
17	19	10
18	19	10
19	18	10
20	18	10
21	18	9
22	18	9
23	18	9
24	18	9
25	18	9
26	17	9
27	17	9
28	17	9
29	17	9
30	17	9

	Clearer (%)	Cloudier (%)
1	54	46
2	54	46
3	53	47
4	53	47
5	53	47
6	53	47
7	53	47
8	52	48
9	52	48
10	51	49
11	51	49
12	50	50
13	49	51
14	49	51
15	48	52
16	47	53
17	46	54
18	45	55
19	43	57
20	43	57
21	42	58
22	42	58
23	41	59
24	40	60
25	40	60
26	39	61
27	39	61
28	37	63
29	37	63
30	36	64

	Rain chance (%)
1	38
2	38
3	38
4	38
5	38
6	38
7	38
8	38
9	38
10	39
11	39
12	40
13	40
14	40
15	41
16	41
17	41
18	41
19	42
20	42
21	42
22	42
23	43
24	43
25	43
26	44
27	44
28	45
29	45
30	45

	Dry (%)	Comfortable (%)	Humid (%)
1	57	32	11
2	58	32	10
3	60	31	9
4	61	31	8
5	63	30	7
6	64	30	6
7	66	29	5
8	67	29	4
9	68	28	4
10	69	28	3
11	70	27	3
12	71	27	2
13	72	26	2
14	74	25	1
15	74	25	1
16	75	24	1
17	77	23	0
18	78	22	0
19	80	20	0
20	81	19	0
21	82	18	0
22	83	17	0
23	84	16	0
24	85	15	0
25	86	14	0
26	87	13	0
27	87	13	0
28	88	12	0
29	89	11	0
30	90	10	0

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

	Clearer (%)	Cloudier (%)
1	54	46
2	54	46
3	53	47
4	53	47
5	53	47
6	53	47
7	53	47
8	52	48
9	52	48
10	51	49
11	51	49
12	50	50
13	49	51
14	49	51
15	48	52
16	47	53
17	46	54
18	45	55
19	43	57
20	43	57
21	42	58
22	42	58
23	41	59
24	40	60
25	40	60
26	39	61
27	39	61
28	37	63
29	37	63
30	36	64

	Rain chance (%)
1	38
2	38
3	38
4	38
5	38
6	38
7	38
8	38
9	38
10	39
11	39
12	40
13	40
14	40
15	41
16	41
17	41
18	41
19	42
20	42
21	42
22	42
23	43
24	43
25	43
26	44
27	44
28	45
29	45
30	45

	Dry (%)	Comfortable (%)	Humid (%)
1	57	32	11
2	58	32	10
3	60	31	9
4	61	31	8
5	63	30	7
6	64	30	6
7	66	29	5
8	67	29	4
9	68	28	4
10	69	28	3
11	70	27	3
12	71	27	2
13	72	26	2
14	74	25	1
15	74	25	1
16	75	24	1
17	77	23	0
18	78	22	0
19	80	20	0
20	81	19	0
21	82	18	0
22	83	17	0
23	84	16	0
24	85	15	0
25	86	14	0
26	87	13	0
27	87	13	0
28	88	12	0
29	89	11	0
30	90	10	0

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

	Clearer (%)	Cloudier (%)
1	54	46
2	54	46
3	53	47
4	53	47
5	53	47
6	53	47
7	53	47
8	52	48
9	52	48
10	51	49
11	51	49
12	50	50
13	49	51
14	49	51
15	48	52
16	47	53
17	46	54
18	45	55
19	43	57
20	43	57
21	42	58
22	42	58
23	41	59
24	40	60
25	40	60
26	39	61
27	39	61
28	37	63
29	37	63
30	36	64

	Rain chance (%)
1	38
2	38
3	38
4	38
5	38
6	38
7	38
8	38
9	38
10	39
11	39
12	40
13	40
14	40
15	41
16	41
17	41
18	41
19	42
20	42
21	42
22	42
23	43
24	43
25	43
26	44
27	44
28	45
29	45
30	45

	Dry (%)	Comfortable (%)	Humid (%)
1	57	32	11
2	58	32	10
3	60	31	9
4	61	31	8
5	63	30	7
6	64	30	6
7	66	29	5
8	67	29	4
9	68	28	4
10	69	28	3
11	70	27	3
12	71	27	2
13	72	26	2
14	74	25	1
15	74	25	1
16	75	24	1
17	77	23	0
18	78	22	0
19	80	20	0
20	81	19	0
21	82	18	0
22	83	17	0
23	84	16	0
24	85	15	0
25	86	14	0
26	87	13	0
27	87	13	0
28	88	12	0
29	89	11	0
30	90	10	0