Humacao weather in September

In September, Humacao sees average daytime highs of 29°C and overnight lows near 25°C, with 170 mm of rain across 25.5 wet days and about 12.1 hours of daylight. It is the 1st-warmest and 1st-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 21% of the time in September, and the air most often feels miserable.

Daylight stretches from about 12 h 24 min at the start of September to 11 h 54 min by month's end. Set against the rest of the year, September is Humacao's 11th-clearest and 11th-windiest month. For the whole year in context, see Humacao's year-round climate.

Daytime high
29°
1st warmest
Overnight low
25°
11th coldest
Rainfall
170 mm
25.5 wet days
Daylight
12 h 06 min
6:15 AM – 6:21 PM
Cloud cover
66%
11th clearest
Wind
12 km/h
11th windiest
Solar energy
5.81 kWh/m²
Travel score
3.5
out of 10

Humacao is historical and administrative center (seat) of Humacao, Puerto Rico.

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 29°C through the month.

A typical September day in Humacao reaches about 29°C in the afternoon and slips back to 25°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 30°C. Set against its neighbours, September runs on par with August and on par with October.

20°23°25°28°30°151015202530
Avg high (°C)Avg low (°C)
12926
22926
32926
42926
52926
62926
72926
82926
92926
102926
112926
122926
132926
142926
152925
162925
172925
182925
192925
202925
212925
222925
232925
242925
252925
262925
272925
282925
292925
302925

How September really feels in Humacao

Once humidity and wind are folded in, September averages 30 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
30
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Humacao weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 23°6019115.7
Feb26° / 23°4816.511.45.9
Mar26° / 23°5817.111.95.9
Apr27° / 23°8219.712.45.2
May27° / 24°13624.212.84.4
Jun28° / 25°10823.113.14.1
Jul28° / 25°13524.7134.0
Aug29° / 26°14626.712.63.6
Sep29° / 25°17025.512.13.5
Oct28° / 25°1602611.63.7
Nov27° / 24°14023.811.14.5
Dec26° / 24°7419.910.95.4

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 21% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 21% of September, with mostly cloudy or overcast conditions the remaining 58%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14555
24555
34555
44555
54555
64753
74753
84753
94654
104654
114555
124555
134456
144357
154258
164159
174159
184060
193961
203862
213862
223763
233862
243862
253862
263961
273961
284060
294060
304060

Chance of precipitation in September

Any precipitation

Humacao gets around 170 mm of rain over 25.5 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 85% and peaks near 87% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
185
285
385
484
584
684
784
884
984
1084
1185
1285
1385
1485
1585
1686
1786
1886
1986
2086
2186
2286
2386
2486
2586
2686
2786
2886
2987
3087

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 70% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
12476
22575
32575
42575
52674
62674
72674
82773
92773
102872
112872
122971
132971
142971
153070
163070
173070
183169
193169
203268
213268
223268
233367
243367
253466
263565
273664
283763
293862
303961

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 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
1912calm
2012calm
2112calm
2212calm
2312calm
2412calm
2512calm
2612calm
2712calm
2812calm
2911calm
3011calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 24 min at the start of September to 11 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 30 minutes over September. Sunrise moves from 6:12 AM to 6:17 AM, and sunset from 6:34 PM to 6:08 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:126:34
212.36:126:33
312.36:136:32
412.36:136:31
512.36:136:30
612.36:136:30
712.36:136:29
812.26:136:28
912.26:146:27
1012.26:146:26
1112.26:146:25
1212.26:146:24
1312.26:146:23
1412.16:146:22
1512.16:146:22
1612.16:156:21
1712.16:156:20
1812.16:156:19
1912.06:156:18
2012.06:156:17
2112.06:156:16
2212.06:166:15
2312.06:166:14
2412.06:166:14
2511.96:166:13
2611.96:166:12
2711.96:166:11
2811.96:176:10
2911.96:176:09
3011.96:176:08

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.81 kWh/m².

For context, solar energy here swings from a low near 4.4 kWh/m² to a high of 6.54 kWh/m² in April across the year — September's 5.81 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.1Intense
46.1Intense
56.0Intense
66.0Intense
76.0Intense
86.0Intense
96.0Bright
106.0Bright
115.9Bright
125.9Bright
135.9Bright
145.8Bright
155.8Bright
165.8Bright
175.8Bright
185.8Bright
195.7Bright
205.7Bright
215.7Bright
225.7Bright
235.6Bright
245.6Bright
255.6Bright
265.6Bright
275.5Bright
285.5Bright
295.5Bright
305.5Bright
Planning a trip in September

Hazard calendar for Humacao

In seasonPeak

In September, Humacao sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Humacao sits in the Atlantic hurricane belt; the season peaks August–October.

Humacao sees seasonal dust haze (July), heaviest in July.

Atlantic hurricane
Dust
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Humacao?

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

3.5
Sightseeing
12th-best month of the year
4.4
Beach & pool
12th-best month of the year

September is a weaker month for outdoor sightseeing in Humacao.

What to pack for Humacao in September

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

In September, Humacao sees daytime highs around 29°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 26 days see rain.

light clothesrain gearsun protection

Sea temperature near Humacao in September

The nearest coast averages about 29°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 22 km away) is warmest in September at about 29°C and coldest in February near 26°C.

The water stays above 20°C all year — warm enough for a swim any month.

24°26°28°30°JanFebMarAprMayJunJulAugSepOctNovDecwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan27Warm
Feb26Warm
Mar26Warm
Apr27Warm
May28Warm
Jun28Tropical
Jul28Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov28Tropical
Dec27Warm

UV index in Humacao in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Humacao peaks around April 12 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 7 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highApr 12UV 13Dec 16UV 7
UV index (midday)Level
Jan8Very high
Feb10Extreme
Mar13Extreme
Apr13Extreme
May12Extreme
Jun12Extreme
Jul12Extreme
Aug12Extreme
Sep12Extreme
Oct10Very high
Nov8Very high
Dec7High

Air quality in Humacao 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 Humacao is worst in July — around 25 µg/m³ PM2.5 (moderate), about 4.7× the cleanest month (January, 5 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1125 µg/m³Jan 15 µg/m³
PM2.5 (µg/m³)Level
Jan5Good
Feb7Good
Mar7Good
Apr9Good
May14Moderate
Jun24Moderate
Jul25Moderate
Aug20Moderate
Sep15Moderate
Oct15Moderate
Nov8Good
Dec5Good
Location & terrain

Where is Humacao?

Humacao sits at 18.1°N, 65.8°W, 22 m above sea level, in Puerto Rico. The nearest listed city is Caguas, 25 km away.

CaguasFajardoCarolinaTrujillo AltoGuayamaCayeyGuaynaboBayamón

Topography around Humacao

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

Within 3 km, the terrain around Humacao has significant variations in elevation — a maximum elevation change of 271 m around an average of 68 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 1,052 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,298 m.

The land around Humacao is covered by trees (65%) and artificial surfaces (24%) within 3 km, trees (55%) and water (24%) within 16 km, and water (69%) and trees (24%) within 80 km.

3 km
271 m
16 km
1,052 m
80 km
1,298 m
treesgrasslandartificial surfaceswaterwetland
September weather nearby: Caguas 25 km · Fajardo 27 km · Carolina 29 km · Trujillo Alto 30 km · Guayama 35 km · Cayey 36 km · Guaynabo 38 km · Bayamón 44 km

Puerto Rico travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 78% of US
price level, 2025
GDP per capita
$40,620
2025
Happiness
7.0 / 10
World Happiness, 2015
Safe drinking water
99%
of population, 2024
Homicide rate
14.6
per 100k, 2023
Income group
High
World Bank
Religion
Roman Catholic 56%Protestant 33%none 7%other 2%

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 Humacao (18.1497°, -65.8274°, elevation 22 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).