Puerto Rico weather in September

In September, Puerto Rico sees average daytime highs of 26°C and overnight lows near 15°C, with 153 mm of rain across 10.2 wet days and about 11.8 hours of daylight. It is the 8th-warmest and 7th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 45% of the time in September, and the air most often feels dry.

Daylight stretches from about 11 h 24 min at the start of September to 12 h 12 min by month's end. Set against the rest of the year, September is Puerto Rico's 3rd-clearest and 2nd-windiest month. For the whole year in context, see Puerto Rico's year-round climate.

Daytime high
26°
8th warmest
Overnight low
15°
5th coldest
Rainfall
153 mm
10.2 wet days
Daylight
11 h 48 min
6:39 AM – 6:30 PM
Cloud cover
49%
3rd clearest
Wind
10 km/h
2nd windiest
Solar energy
4.66 kWh/m²
Travel score
6.8
out of 10

Puerto Rico is capital city of the Libertador General San Martín Department, in the Misiones Province of Argentina.

Founded
1919

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Puerto Rico reaches about 26°C in the afternoon and slips back to 15°C overnight — a 11°C spread between the day's warmth and the night's chill. On most days the high lands between 19°C and 33°C. Set against its neighbours, September runs about 2°C warmer than August and about 2°C cooler than October.

10°20°30°151015202530
Avg high (°C)Avg low (°C)
12514
22514
32514
42514
52514
62514
72614
82614
92614
102614
112614
122614
132614
142615
152615
162615
172615
182615
192615
202615
212615
222615
232615
242615
252615
262615
272615
282615
292616
302616

How September really feels in Puerto Rico

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
0
heat index over the day's high
Days feeling ≤ C
0
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.

Puerto Rico weather by month

How September compares with the rest of the year at a glance. September is the 8th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan32° / 21°15114.913.53.7
Feb31° / 21°15414.412.94.0
Mar30° / 20°13711.912.24.9
Apr27° / 17°1419.711.46.5
May23° / 14°1629.210.77.0
Jun21° / 12°1549.110.36.7
Jul21° / 11°1259.110.56.9
Aug24° / 13°907.611.17.6
Sep26° / 15°15310.211.86.8
Oct28° / 17°20613.212.65.8
Nov30° / 18°16711.413.35.1
Dec31° / 20°1811413.74.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 45% 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 43%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
16535
26436
36436
46337
56337
66238
76238
86040
96040
105941
115941
125941
135941
145842
155842
165842
175743
185743
195644
205644
215545
225545
235446
245446
255347
265347
275248
285149
295050
305050

Chance of precipitation in September

Any precipitation

Puerto Rico gets around 153 mm of rain over 10.2 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 34% and peaks near 40% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
126
226
326
427
527
628
729
829
930
1031
1132
1232
1333
1434
1535
1635
1736
1837
1937
2038
2138
2239
2339
2439
2539
2640
2740
2840
2940
3040

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 31% of days. Sticky, muggy-or-worse air turns up on roughly 14% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
136312760
236302770
335302780
435302780
534292790
634292890
7342928100
8332828100
9332828110
10322729110
11322729110
12322729121
13312629121
14312630121
15312630131
16312530131
17312530131
18312430131
19312431131
20312431141
21302431141
22292431151
23292430161
24282430171
25272430181
26262430191
27252430201
28242330221
29232330231
30222330241

Wind in September

Winds average 10 km/h in September.

Across September, daily wind ranges from about 9 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
169calm
179calm
189calm
199calm
209calm
219calm
229calm
239calm
249calm
259calm
269calm
279calm
289calm
299calm
309calm

Sunrise & sunset in September

DaylightNight

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

Days grow by about 48 minutes over September. Sunrise moves from 6:56 AM to 6:23 AM, and sunset from 6:23 PM to 6:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.46:566:23
211.56:556:24
311.56:546:24
411.56:536:24
511.56:526:25
611.66:516:25
711.66:506:26
811.66:496:26
911.76:476:27
1011.76:466:27
1111.76:456:28
1211.76:446:28
1311.86:436:28
1411.86:416:29
1511.86:406:29
1611.86:396:30
1711.96:386:30
1811.96:376:31
1911.96:366:31
2012.06:346:31
2112.06:336:32
2212.06:326:32
2312.06:316:33
2412.16:306:33
2512.16:286:34
2612.16:276:34
2712.16:266:35
2812.26:256:35
2912.26:246:36
3012.26:236:36

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.66 kWh/m².

For context, solar energy here swings from a low near 2.69 kWh/m² to a high of 6.44 kWh/m² in December across the year — September's 4.66 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.5Bright
34.5Bright
44.5Bright
54.5Bright
64.5Bright
74.5Bright
84.6Bright
94.6Bright
104.6Bright
114.6Bright
124.6Bright
134.6Bright
144.6Bright
154.7Bright
164.7Bright
174.7Bright
184.7Bright
194.7Bright
204.7Bright
214.8Bright
224.8Bright
234.8Bright
244.8Bright
254.8Bright
264.8Bright
274.8Bright
284.9Bright
294.9Bright
304.9Bright
Planning a trip in September

Is September a good time to visit Puerto Rico?

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

6.8
Sightseeing
4th-best month of the year
6.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Puerto Rico for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Puerto Rico in September

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

In September, Puerto Rico sees daytime highs around 26°C and nights near 15°C. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

UV index in Puerto Rico in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Puerto Rico peaks around January 18 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 22 at about 4 (moderate).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeVery highHighModerateHighVery highExtremeJan 18UV 14Jun 22UV 4
UV index (midday)Level
Jan14Extreme
Feb13Extreme
Mar12Extreme
Apr8Very high
May6High
Jun4Moderate
Jul4Moderate
Aug6High
Sep8Very high
Oct8Very high
Nov11Extreme
Dec13Extreme

Air quality in Puerto Rico 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 Puerto Rico is worst in September — around 19 µg/m³ PM2.5 (moderate), about 2.8× the cleanest month (December, 7 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodSep 1318 µg/m³Dec 177 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar7Good
Apr8Good
May7Good
Jun7Good
Jul10Good
Aug16Moderate
Sep19Moderate
Oct11Good
Nov8Good
Dec7Good
Location & terrain

Where is Puerto Rico?

Puerto Rico sits at 26.8°S, 55.0°W, 188 m above sea level, in Argentina. The nearest listed city is Jardín América, 33 km away.

Topography around Puerto Rico

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

Within 3 km, the terrain around Puerto Rico has only modest variations in elevation — a maximum elevation change of 161 m around an average of 158 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 250 m; within 80 km, significant variations in elevation — a maximum elevation change of 550 m.

The land around Puerto Rico is covered by trees (52%) and grassland (24%) within 3 km, trees (59%) and cropland (21%) within 16 km, and trees (65%) and cropland (24%) within 80 km.

3 km
161 m
16 km
250 m
80 km
550 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Jardín América 33 km · Montecarlo 37 km · Eldorado 60 km · Oberá 76 km · Trinidad 77 km · San Vicente 91 km · San Pedro 93 km · Leandro N. Alem 93 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 Puerto Rico (-26.8089°, -55.0215°, elevation 188 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).