San Nicolás de los Arroyos weather in September

In September, San Nicolás de los Arroyos sees average daytime highs of 21°C and overnight lows near 10°C, with 67 mm of rain across 6.3 wet days and about 11.8 hours of daylight. It is the 8th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 20°C in the first days to 22°C by the end. The sky is clear or mostly clear about 47% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 18 min at the start of September to 12 h 18 min by month's end. Set against the rest of the year, September is San Nicolás de los Arroyos's 7th-clearest and 1st-windiest month. For the whole year in context, see San Nicolás de los Arroyos's year-round climate.

Daytime high
21°
8th warmest
Overnight low
10°
4th coldest
Rainfall
67 mm
6.3 wet days
Daylight
11 h 48 min
7:01 AM – 6:49 PM
Cloud cover
47%
7th clearest
Wind
12 km/h
1st windiest
Solar energy
4.71 kWh/m²
Travel score
7.1
out of 10

San Nicolás de los Arroyos is city in Argentina.

Founded
1748

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 20°C in the first days to 22°C by the end.

A typical September day in San Nicolás de los Arroyos reaches about 21°C in the afternoon and slips back to 10°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 26°C. Set against its neighbours, September runs about 2°C warmer than August and about 3°C cooler than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
1209
2209
3209
4209
5209
6209
7209
8209
9209
102010
112010
122010
132010
142110
152110
162110
172110
182110
192110
202110
212110
222110
232110
242110
252111
262111
272111
282211
292211
302211

San Nicolás de los Arroyos weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan30° / 19°1038.2145.4
Feb29° / 19°1078.113.25.9
Mar27° / 17°1177.512.37.0
Apr23° / 14°1068.111.27.4
May19° / 11°66610.36.8
Jun16° / 445.29.85.8
Jul16° / 425.1105.6
Aug18° / 56510.86.8
Sep21° / 10°676.311.87.1
Oct23° / 13°1129.712.87.1
Nov26° / 15°1157.613.77.2
Dec29° / 18°1078.614.26.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 47% 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 40%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15743
25743
35743
45842
55941
65941
76040
86139
96238
106337
116337
126337
136337
146436
156436
166436
176436
186337
196337
206238
216139
226040
235941
245842
255842
265644
275644
285644
295545
305545

Chance of precipitation in September

Any precipitation

San Nicolás de los Arroyos gets around 67 mm of rain over 6.3 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 21% and peaks near 26% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
122
222
323
423
523
622
722
821
921
1020
1120
1220
1319
1419
1519
1619
1719
1819
1919
2019
2120
2220
2321
2421
2522
2623
2724
2824
2925
3026

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 81% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
1811261
2821161
3831160
4831160
5821170
6821170
7821170
8821170
9831160
10831160
11831160
12831160
13831160
14821161
15831151
16831151
17831151
18831151
19821251
20831241
21821341
22821341
23801451
24801451
25791551
26791551
27771661
28771661
29751771
30751771

Wind in September

Winds average 12 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 12 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1012light breeze
1112light breeze
1212light breeze
1312light breeze
1412light breeze
1512light breeze
1612light breeze
1712light breeze
1812light breeze
1912light breeze
2012light breeze
2112light breeze
2212light breeze
2312light breeze
2412light breeze
2512light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 18 min at the start of September to 12 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over September. Sunrise moves from 7:22 AM to 6:41 AM, and sunset from 6:39 PM to 6:59 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.37:226:39
211.37:216:39
311.37:206:40
411.47:186:41
511.47:176:42
611.47:156:42
711.57:146:43
811.57:136:44
911.67:116:44
1011.67:106:45
1111.67:086:46
1211.77:076:46
1311.77:066:47
1411.77:046:48
1511.87:036:48
1611.87:016:49
1711.87:006:50
1811.96:586:50
1911.96:576:51
2011.96:566:52
2112.06:546:53
2212.06:536:53
2312.06:516:54
2412.16:506:55
2512.16:486:55
2612.26:476:56
2712.26:466:57
2812.26:446:57
2912.36:436:58
3012.36:416:59

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.71 kWh/m².

For context, solar energy here swings from a low near 2.34 kWh/m² to a high of 7.31 kWh/m² in December across the year — September's 4.71 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
14.1Bright
24.1Bright
34.2Bright
44.2Bright
54.3Bright
64.3Bright
74.4Bright
84.4Bright
94.5Bright
104.5Bright
114.6Bright
124.6Bright
134.7Bright
144.7Bright
154.8Bright
164.8Bright
174.8Bright
184.9Bright
194.9Bright
204.9Bright
215.0Bright
225.0Bright
235.0Bright
245.0Bright
255.0Bright
265.0Bright
275.0Bright
285.1Bright
295.1Bright
305.1Bright
Planning a trip in September

Is September a good time to visit San Nicolás de los Arroyos?

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

7.1
Sightseeing
3rd-best month of the year
4.1
Beach & pool
8th-best month of the year

September is one of the better times to visit San Nicolás de los Arroyos for general sightseeing.

What to pack for San Nicolás de los Arroyos in September

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

In September, San Nicolás de los Arroyos sees daytime highs around 21°C and nights near 10°C. Worth packing: sun protection. About 6 days see rain.

sun protection

UV index in San Nicolás de los Arroyos in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Nicolás de los Arroyos peaks around January 15 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 19 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highModerateHighVery highExtremeJan 15UV 13Jun 19UV 3
UV index (midday)Level
Jan14Extreme
Feb12Extreme
Mar10Very high
Apr6High
May4Moderate
Jun3Moderate
Jul3Moderate
Aug4Moderate
Sep6High
Oct9Very high
Nov11Extreme
Dec12Extreme

Air quality in San Nicolás de los Arroyos 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 San Nicolás de los Arroyos is worst in August — around 46 µg/m³ PM2.5 (poor), about 8.0× the cleanest month (April, 6 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecGoodModeratePoorModerateGoodAug 1544 µg/m³Apr 146 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb7Good
Mar7Good
Apr6Good
May7Good
Jun10Good
Jul28Moderate
Aug46Poor
Sep20Moderate
Oct14Moderate
Nov8Good
Dec7Good
Location & terrain

Where is San Nicolás de los Arroyos?

San Nicolás de los Arroyos sits at 33.3°S, 60.2°W, 28 m above sea level, in Argentina. The nearest listed city is Villa Constitución, 16 km away.

Topography around San Nicolás de los Arroyos

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of San Nicolás de los Arroyos.

Within 3 km, the terrain around San Nicolás de los Arroyos has only modest variations in elevation — a maximum elevation change of 38 m around an average of 16 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 53 m; within 80 km, only modest variations in elevation — a maximum elevation change of 98 m.

The land around San Nicolás de los Arroyos is covered by artificial surfaces (42%) within 3 km, cropland (39%) and wetland (32%) within 16 km, and cropland (50%) and wetland (31%) within 80 km.

3 km
38 m
16 km
53 m
80 km
98 m
treesgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Villa Constitución 16 km · Ramallo 25 km · Arroyo Seco 34 km · Gobernador Gálvez 52 km · Rosario 59 km · San Pedro 63 km · Pérez 64 km · Pergamino 70 km

Argentina travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type C / I
220 V · 50 Hz
Prices
≈ 46% of US
price level, 2025
GDP per capita
$14,898
2025
Happiness
6.4 / 10
World Happiness, 2025
Homicide rate
4.5
per 100k, 2023
Road deaths
14.1
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
High
EF EPI 575
Religion
Roman Catholic 63%none 19%Evangelical 15%Jehovah's Witness and Church of Jesus Christ 1%

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 San Nicolás de los Arroyos (-33.3342°, -60.2108°, elevation 28 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).