Santiago weather in September

In September, Santiago sees average daytime highs of 26°C and overnight lows near 17°C, with 191 mm of rain across 16.2 wet days and about 12.2 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 27°C in the first days to 25°C by the end. The sky is clear or mostly clear about 37% of the time in September, and the air most often feels humid.

Daylight stretches from about 12 h 30 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Santiago's 12th-clearest and 10th-windiest month. For the whole year in context, see Santiago's year-round climate.

Daytime high
26°
5th warmest
Overnight low
17°
9th coldest
Rainfall
191 mm
16.2 wet days
Daylight
12 h 06 min
6:31 AM – 6:39 PM
Cloud cover
54%
12th clearest
Wind
5 km/h
10th windiest
Solar energy
5.26 kWh/m²
Travel score
5.8
out of 10

Santiago is municipal seat of Santiago, State of Nuevo León, Mexico.

Founded
1648

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 27°C in the first days to 25°C by the end.

A typical September day in Santiago reaches about 26°C in the afternoon and slips back to 17°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 23°C and 29°C. Set against its neighbours, September runs about 3°C cooler than August and about 3°C warmer than October.

10°15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12718
22718
32718
42718
52718
62718
72718
82718
92718
102718
112617
122617
132617
142617
152617
162617
172617
182617
192617
202617
212617
222617
232617
242516
252516
262516
272516
282516
292516
302516

Santiago weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan17° / 609.310.65.9
Feb20° / 8410.111.16.3
Mar22° / 11°13114.211.86.2
Apr25° / 14°17215.612.66.1
May27° / 16°1581613.25.9
Jun28° / 18°871113.66.0
Jul29° / 18°8810.413.45.8
Aug29° / 18°6810.412.95.9
Sep26° / 17°19116.212.25.8
Oct24° / 14°10711.111.47.0
Nov20° / 10°669.210.86.7
Dec18° / 477.110.46.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 37% of the time in September, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 47%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15545
25446
35446
45347
55248
65248
75149
85149
94951
104951
114951
125050
135050
145050
154951
164951
175050
185050
195050
205149
215248
225446
235545
245743
255842
266040
276040
286238
296337
306436

Chance of precipitation in September

Any precipitation

Santiago gets around 191 mm of rain over 16.2 wet days in September, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 52% and peaks near 58% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%151015202530
Rain chance (%)
151
252
353
454
555
656
757
857
958
1058
1158
1258
1358
1458
1557
1657
1756
1855
1954
2053
2152
2250
2349
2447
2546
2644
2743
2842
2941
3041

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels humid — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the humid band about 47% of days. Sticky, muggy-or-worse air turns up on roughly 32% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
12125432
22125333
32125333
42125234
53115234
63115135
73115135
83115135
93105136
103105136
113105136
123115036
133114936
144114936
154124836
164124736
174134736
185144635
196154534
207164433
218174332
229184231
2310194130
2411204128
2512204027
2613214025
2714214124
2815224122
2916224120
3017224219

Wind in September

Winds average 5 km/h in September.

Across September, daily wind ranges from about 5 km/h on the calmest days to 5 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 30 min at the start of September to 11 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 42 minutes over September. Sunrise moves from 6:25 AM to 6:36 AM, and sunset from 6:56 PM to 6:24 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.56:256:56
212.56:256:55
312.56:256:54
412.46:266:53
512.46:266:52
612.46:276:51
712.46:276:49
812.36:276:48
912.36:286:47
1012.36:286:46
1112.36:296:45
1212.26:296:44
1312.26:296:43
1412.26:306:42
1512.26:306:40
1612.16:316:39
1712.16:316:38
1812.16:316:37
1912.16:326:36
2012.06:326:35
2112.06:336:34
2212.06:336:33
2312.06:336:31
2411.96:346:30
2511.96:346:29
2611.96:356:28
2711.96:356:27
2811.86:356:26
2911.86:366:25
3011.86:366:24

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.26 kWh/m².

For context, solar energy here swings from a low near 3.73 kWh/m² to a high of 6.76 kWh/m² in June across the year — September's 5.26 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.7Bright
25.7Bright
35.6Bright
45.6Bright
55.5Bright
65.5Bright
75.4Bright
85.4Bright
95.4Bright
105.3Bright
115.3Bright
125.3Bright
135.3Bright
145.3Bright
155.2Bright
165.2Bright
175.2Bright
185.2Bright
195.2Bright
205.2Bright
215.2Bright
225.2Bright
235.2Bright
245.2Bright
255.2Bright
265.2Bright
275.2Bright
285.2Bright
295.2Bright
305.2Bright
Planning a trip in September

Is September a good time to visit Santiago?

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

5.8
Sightseeing
11th-best month of the year
5.7
Beach & pool
5th-best month of the year

September is a reasonable time to visit Santiago for sightseeing.

What to pack for Santiago in September

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

In September, Santiago sees daytime highs around 26°C and nights near 17°C. Pack rain gear. Worth having: light clothes and sun protection. About 16 days see rain.

rain gearlight clothessun protection

UV index in Santiago in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Santiago peaks around June 21 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 5 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecHighVery highExtremeVery highHighJun 21UV 11Dec 19UV 5
UV index (midday)Level
Jan5High
Feb7Very high
Mar9Very high
Apr11Extreme
May11Extreme
Jun12Extreme
Jul11Extreme
Aug12Extreme
Sep9Very high
Oct8Very high
Nov6High
Dec5Moderate

Air quality in Santiago 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 Santiago is worst in December — around 24 µg/m³ PM2.5 (moderate), and holds fairly steady the rest of the year.

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateDec 1724 µg/m³Aug 1518 µg/m³
PM2.5 (µg/m³)Level
Jan23Moderate
Feb21Moderate
Mar24Moderate
Apr21Moderate
May22Moderate
Jun20Moderate
Jul19Moderate
Aug18Moderate
Sep20Moderate
Oct20Moderate
Nov22Moderate
Dec24Moderate
Location & terrain

Where is Santiago?

Santiago sits at 25.4°N, 100.2°W, 486 m above sea level, in Mexico. The nearest listed city is Ciudad de Allende, 21 km away.

Topography around Santiago

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

Within 3 km, the terrain around Santiago has significant variations in elevation — a maximum elevation change of 452 m around an average of 513 m above sea level; within 16 km, extreme variations in elevation — a maximum elevation change of 2,598 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,555 m.

The land around Santiago is covered by trees (68%) within 3 km, trees (81%) within 16 km, and shrubs (47%) and trees (36%) within 80 km.

3 km
452 m
16 km
2,598 m
80 km
3,555 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Ciudad de Allende 21 km · Jardines de la Silla 23 km · Cadereyta Jiménez 24 km · Cadereyta 24 km · Ciudad Benito Juárez 25 km · Guadalupe 30 km · Monterrey 33 km · San Pedro Garza García 36 km

Mexico travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B
120 / 127 V · 60 Hz
Prices
≈ 54% of US
price level, 2025
GDP per capita
$13,889
2025
Happiness
7.0 / 10
World Happiness, 2025
Safe drinking water
43%
of population, 2024
Homicide rate
24.9
per 100k, 2023
Road deaths
12.8
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Very low
EF EPI 440
Religion
Catholic 78%no religion 11%other Evangelical Churches 8%Jehovah Witness 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 Santiago (25.426°, -100.154°, elevation 486 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).