La Unión weather in September

In September, La Unión sees average daytime highs of 13°C and overnight lows near 5°C, with 125 mm of precipitation across 13.5 wet days and about 11.7 hours of daylight. It is the 8th-warmest and 5th-wettest month of the year here.

Highs climb over the month, from about 12°C in the first days to 14°C by the end. The sky is clear or mostly clear about 15% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 06 min at the start of September to 12 h 24 min by month's end. Set against the rest of the year, September is La Unión's 8th-clearest and 10th-windiest month. For the whole year in context, see La Unión's year-round climate.

Daytime high: 13°; 8th warmest
Overnight low: 5°; 4th coldest
Precipitation: 125 mm; 13.5 wet days
Daylight: 11 h 42 min; 7:55 AM – 7:39 PM
Cloud cover: 69%; 8th clearest
Wind: 10 km/h; 10th windiest
Solar energy: 3.5 kWh/m²
Travel score: 3.4; out of 10

La Unión is city in Chile.

Air quality: High; PM2.5 29.9 µg/m³ · 2019
Density: 12/km²; people per km²
Founded: 1821

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

← August La Unión 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 climb over the month, from about 12°C in the first days to 14°C by the end.

A typical September day in La Unión reaches about 13°C in the afternoon and slips back to 5°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 10°C and 17°C. Set against its neighbours, September runs about 2°C warmer than August and about 2°C cooler 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)	12	12	12	12	13	13	13	13	13	13	13	13	13	13	13	13	13	14	14	14	14	14	14	14	14	14	14	14	14	14
Avg low (°C)	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	4	5	5	5	5	5	5	5	5	5	5	5	5	5

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

La Unión weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 5th-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Daylight (hours)	Travel score
Jan	22° / 10°	36	6	14.5	7.5
Feb	22° / 10°	41	5.1	13.6	7.6
Mar	20° / 9°	63	7.6	12.3	6.7
Apr	16° / 7°	109	10.6	11	4.9
May	13° / 6°	189	15.4	9.8	3.1
Jun	11° / 4°	254	18.3	9.2	2.0
Jul	10° / 4°	229	17.8	9.4	1.9
Aug	11° / 4°	210	17.8	10.4	2.3
Sep	13° / 5°	125	13.5	11.7	3.4
Oct	15° / 6°	110	13.4	13.1	4.3
Nov	17° / 8°	74	9.9	14.2	5.5
Dec	20° / 9°	64	8	14.8	6.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 15% 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 67%.

	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 (%)	30	32	33	34	35	35	36	36	36	35	35	35	35	34	34	34	34	34	34	34	33	32	32	32	32	32	32	31	31	31
Cloudier (%)	70	68	67	66	65	65	64	64	64	65	65	65	65	66	66	66	66	66	66	66	67	68	68	68	68	68	68	69	69	69

	Clearer (%)	Cloudier (%)
1	30	70
2	32	68
3	33	67
4	34	66
5	35	65
6	35	65
7	36	64
8	36	64
9	36	64
10	35	65
11	35	65
12	35	65
13	35	65
14	34	66
15	34	66
16	34	66
17	34	66
18	34	66
19	34	66
20	34	66
21	33	67
22	32	68
23	32	68
24	32	68
25	32	68
26	32	68
27	32	68
28	31	69
29	31	69
30	31	69

Chance of precipitation in September

Any precipitation

La Unión gets around 125 mm of rain and snow over 13.5 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 46% and peaks near 53% on the wettest days, and about 0 day brings snow. The odds ease 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 (%)	53	53	53	52	51	50	50	49	49	49	48	48	47	47	46	45	44	43	43	42	42	42	42	42	42	42	42	42	42	42

	Rain chance (%)
1	53
2	53
3	53
4	52
5	51
6	50
7	50
8	49
9	49
10	49
11	48
12	48
13	47
14	47
15	46
16	45
17	44
18	43
19	43
20	42
21	42
22	42
23	42
24	42
25	42
26	42
27	42
28	42
29	42
30	42

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 10 km/h in September.

Across September, daily wind ranges from about 10 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)	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10	10
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	10	calm
2	10	calm
3	10	calm
4	10	calm
5	10	calm
6	10	calm
7	10	calm
8	10	calm
9	10	calm
10	10	calm
11	10	calm
12	10	calm
13	10	calm
14	10	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	10	calm
24	10	calm
25	10	calm
26	10	calm
27	10	calm
28	10	calm
29	10	calm
30	10	calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 06 min at the start of September to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 78 minutes over September. Sunrise moves from 8:20 AM to 7:30 AM, and sunset from 7:24 PM to 7:53 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)	11.1	11.1	11.2	11.2	11.2	11.3	11.3	11.4	11.4	11.5	11.5	11.6	11.6	11.6	11.7	11.7	11.8	11.8	11.9	11.9	12.0	12.0	12.1	12.1	12.1	12.2	12.2	12.3	12.3	12.4
Sunrise (AM)	8:20	8:18	8:17	8:15	8:13	8:12	8:10	8:08	8:07	8:05	8:03	8:01	8:00	7:58	7:56	7:55	7:53	7:51	7:49	7:48	7:46	7:44	7:42	7:41	7:39	7:37	7:35	7:34	7:32	7:30
Sunset (PM)	7:24	7:25	7:26	7:27	7:28	7:29	7:30	7:31	7:32	7:33	7:34	7:35	7:36	7:37	7:38	7:39	7:40	7:41	7:42	7:43	7:44	7:45	7:46	7:47	7:48	7:49	7:50	7:51	7:52	7:53

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	11.1	8:20	7:24
2	11.1	8:18	7:25
3	11.2	8:17	7:26
4	11.2	8:15	7:27
5	11.2	8:13	7:28
6	11.3	8:12	7:29
7	11.3	8:10	7:30
8	11.4	8:08	7:31
9	11.4	8:07	7:32
10	11.5	8:05	7:33
11	11.5	8:03	7:34
12	11.6	8:01	7:35
13	11.6	8:00	7:36
14	11.6	7:58	7:37
15	11.7	7:56	7:38
16	11.7	7:55	7:39
17	11.8	7:53	7:40
18	11.8	7:51	7:41
19	11.9	7:49	7:42
20	11.9	7:48	7:43
21	12.0	7:46	7:44
22	12.0	7:44	7:45
23	12.1	7:42	7:46
24	12.1	7:41	7:47
25	12.1	7:39	7:48
26	12.2	7:37	7:49
27	12.2	7:35	7:50
28	12.3	7:34	7:51
29	12.3	7:32	7:52
30	12.4	7:30	7:53

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 3.5 kWh/m².

For context, solar energy here swings from a low near 1.28 kWh/m² to a high of 7.12 kWh/m² in January across the year — September's 3.5 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)	2.8	2.8	2.9	2.9	3.0	3.0	3.1	3.1	3.2	3.2	3.3	3.3	3.4	3.4	3.5	3.5	3.6	3.6	3.6	3.7	3.8	3.8	3.8	3.9	3.9	4.0	4.0	4.1	4.1	4.1
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	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	2.8	Moderate
2	2.8	Moderate
3	2.9	Moderate
4	2.9	Moderate
5	3.0	Moderate
6	3.0	Moderate
7	3.1	Moderate
8	3.1	Moderate
9	3.2	Moderate
10	3.2	Moderate
11	3.3	Moderate
12	3.3	Moderate
13	3.4	Moderate
14	3.4	Moderate
15	3.5	Moderate
16	3.5	Moderate
17	3.6	Moderate
18	3.6	Moderate
19	3.6	Moderate
20	3.7	Moderate
21	3.8	Moderate
22	3.8	Moderate
23	3.8	Moderate
24	3.9	Moderate
25	3.9	Moderate
26	4.0	Moderate
27	4.0	Bright
28	4.1	Bright
29	4.1	Bright
30	4.1	Bright

Planning a trip in September

Hazard calendar for La Unión

In seasonPeak

In September, La Unión sits inside its rainy season season. The full year is below, with each hazard's peak months called out.

La Unión's rainy season runs May–September, when most of the year's rain falls.

Rainy season

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Is September a good time to visit La Unión?

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

3.4

Sightseeing

8th-best month of the year

0.0

Beach & pool

9th-best month of the year

September is a weaker month for outdoor sightseeing in La Unión.

What to pack for La Unión in September

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

In September, La Unión sees daytime highs around 13°C and nights near 5°C. Pack rain gear. Worth having: a warm layer. About 14 days see rain.

rain geara warm layer

Sea temperature near La Unión in September

The nearest coast averages about 11°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 66 km away) is warmest in January at about 14°C and coldest in August near 11°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)	14	14	14	13	13	12	11	11	11	12	13	14
Comfort	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing	Bracing

	Sea temperature (°C)	Comfort
Jan	14	Bracing
Feb	14	Bracing
Mar	14	Bracing
Apr	13	Bracing
May	13	Bracing
Jun	12	Bracing
Jul	11	Bracing
Aug	11	Bracing
Sep	11	Bracing
Oct	12	Bracing
Nov	13	Bracing
Dec	14	Bracing

UV index in La Unión 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 La Unión peaks around December 20 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 18 at about 2 (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)	11	11	7	5	2	2	2	3	4	7	9	12
Level	Extreme	Extreme	Very high	Moderate	Moderate	Low	Low	Moderate	Moderate	High	Very high	Extreme

	UV index (midday)	Level
Jan	11	Extreme
Feb	11	Extreme
Mar	7	Very high
Apr	5	Moderate
May	2	Moderate
Jun	2	Low
Jul	2	Low
Aug	3	Moderate
Sep	4	Moderate
Oct	7	High
Nov	9	Very high
Dec	12	Extreme

Air quality in La Unión 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 La Unión is worst in March — around 36 µg/m³ PM2.5 (poor), about 1.7× the cleanest month (February, 22 µg/m³).

Seasonal pattern from CAMS reanalysis, scaled to La Unión's WHO annual average of 29.9 µg/m³.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
PM2.5 (µg/m³)	24	22	36	36	28	26	27	33	36	33	31	27
Level	Moderate	Moderate	Poor	Poor	Moderate	Moderate	Moderate	Moderate	Poor	Moderate	Moderate	Moderate

	PM2.5 (µg/m³)	Level
Jan	24	Moderate
Feb	22	Moderate
Mar	36	Poor
Apr	36	Poor
May	28	Moderate
Jun	26	Moderate
Jul	27	Moderate
Aug	33	Moderate
Sep	36	Poor
Oct	33	Moderate
Nov	31	Moderate
Dec	27	Moderate

Location & terrain

Where is La Unión?

La Unión sits at 40.3°S, 73.1°W, 32 m above sea level, in Chile. The nearest listed city is Río Bueno, 12 km away.

Topography around La Unión

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

Within 3 km, the terrain around La Unión has only modest variations in elevation — a maximum elevation change of 80 m around an average of 49 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 528 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,782 m.

The land around La Unión is covered by cropland (41%), trees (25%) and grassland (20%) within 3 km, trees (44%), cropland (29%) and grassland (25%) within 16 km, and trees (51%) and grassland (21%) within 80 km.

3 km

80 m

cropland 41%

16 km

528 m

trees 44%

80 km

1,782 m

trees 51%

treesgrasslandcroplandartificial surfaceswater

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

September weather nearby: Río Bueno 12 km · Paillaco 30 km · Osorno 32 km · Valdivia 55 km · Las Animas 55 km · Purranque 69 km · Frutillar 92 km · Panguipulli 96 km

Chile travel facts

Travel advisory: Level 2; Exercise Increased Caution
Power plugs: Type C / F / L; 220 V · 50 Hz
Prices: ≈ 48% of US; price level, 2025
GDP per capita: $17,995; 2025
Happiness: 6.3 / 10; World Happiness, 2025
Safe drinking water: 98%; of population, 2024
Homicide rate: 6.3; per 100k, 2023
Road deaths: 14.9; per 100k/yr, 2019
Income group: High; World Bank
English: Moderate; EF EPI 517
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 La Unión (-40.2931°, -73.0817°, elevation 32 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. 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	12	4
2	12	4
3	12	4
4	12	4
5	13	4
6	13	4
7	13	4
8	13	4
9	13	4
10	13	4
11	13	4
12	13	4
13	13	4
14	13	4
15	13	4
16	13	4
17	13	4
18	14	5
19	14	5
20	14	5
21	14	5
22	14	5
23	14	5
24	14	5
25	14	5
26	14	5
27	14	5
28	14	5
29	14	5
30	14	5

	Clearer (%)	Cloudier (%)
1	30	70
2	32	68
3	33	67
4	34	66
5	35	65
6	35	65
7	36	64
8	36	64
9	36	64
10	35	65
11	35	65
12	35	65
13	35	65
14	34	66
15	34	66
16	34	66
17	34	66
18	34	66
19	34	66
20	34	66
21	33	67
22	32	68
23	32	68
24	32	68
25	32	68
26	32	68
27	32	68
28	31	69
29	31	69
30	31	69

	Rain chance (%)
1	53
2	53
3	53
4	52
5	51
6	50
7	50
8	49
9	49
10	49
11	48
12	48
13	47
14	47
15	46
16	45
17	44
18	43
19	43
20	42
21	42
22	42
23	42
24	42
25	42
26	42
27	42
28	42
29	42
30	42

	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

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

	Clearer (%)	Cloudier (%)
1	30	70
2	32	68
3	33	67
4	34	66
5	35	65
6	35	65
7	36	64
8	36	64
9	36	64
10	35	65
11	35	65
12	35	65
13	35	65
14	34	66
15	34	66
16	34	66
17	34	66
18	34	66
19	34	66
20	34	66
21	33	67
22	32	68
23	32	68
24	32	68
25	32	68
26	32	68
27	32	68
28	31	69
29	31	69
30	31	69

	Rain chance (%)
1	53
2	53
3	53
4	52
5	51
6	50
7	50
8	49
9	49
10	49
11	48
12	48
13	47
14	47
15	46
16	45
17	44
18	43
19	43
20	42
21	42
22	42
23	42
24	42
25	42
26	42
27	42
28	42
29	42
30	42

	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

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

	Clearer (%)	Cloudier (%)
1	30	70
2	32	68
3	33	67
4	34	66
5	35	65
6	35	65
7	36	64
8	36	64
9	36	64
10	35	65
11	35	65
12	35	65
13	35	65
14	34	66
15	34	66
16	34	66
17	34	66
18	34	66
19	34	66
20	34	66
21	33	67
22	32	68
23	32	68
24	32	68
25	32	68
26	32	68
27	32	68
28	31	69
29	31	69
30	31	69

	Rain chance (%)
1	53
2	53
3	53
4	52
5	51
6	50
7	50
8	49
9	49
10	49
11	48
12	48
13	47
14	47
15	46
16	45
17	44
18	43
19	43
20	42
21	42
22	42
23	42
24	42
25	42
26	42
27	42
28	42
29	42
30	42

	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