Guayama weather in September

In September, Guayama sees average daytime highs of 28°C and overnight lows near 25°C, with 167 mm of rain across 24.9 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 28°C through the month. The sky is clear or mostly clear about 24% of the time in September, and the air most often feels oppressive.

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 Guayama's 12th-clearest and 11th-windiest month. For the whole year in context, see Guayama's year-round climate.

Daytime high
28°
1st warmest
Overnight low
25°
12th coldest
Rainfall
167 mm
24.9 wet days
Daylight
12 h 06 min
6:16 AM – 6:22 PM
Cloud cover
65%
12th clearest
Wind
14 km/h
11th windiest
Solar energy
5.78 kWh/m²
Travel score
3.9
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 28°C through the month.

A typical September day in Guayama reaches about 28°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 27°C and 29°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)
12825
22825
32825
42825
52825
62825
72825
82825
92825
102825
112825
122825
132825
142825
152825
162825
172825
182825
192825
202825
212825
222825
232825
242825
252825
262825
272825
282825
292825
302825

How September really feels in Guayama

Once humidity and wind are folded in, September averages 17 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
17
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.

Guayama 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
Jan25° / 23°4816.5116.2
Feb25° / 23°3814.711.46.3
Mar26° / 23°4614.411.96.4
Apr26° / 23°6317.112.45.7
May27° / 24°11622.512.84.7
Jun28° / 25°9521.913.14.6
Jul28° / 25°11323134.6
Aug28° / 25°13024.712.64.2
Sep28° / 25°16724.912.13.9
Oct28° / 25°14625.111.64.2
Nov27° / 24°11321.211.24.9
Dec26° / 23°6017.710.95.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 24% of the time in September, the cloudiest month of the year.

Beyond those clear spells, partly cloudy skies cover about 20% of September, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
14852
24852
34951
44951
54951
64852
74852
84852
94852
104852
114852
124654
134654
144555
154456
164456
174258
184159
194159
203961
213961
223862
233961
243961
253961
263961
273961
283961
294159
304159

Chance of precipitation in September

Any precipitation

Guayama gets around 167 mm of rain over 24.9 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 83% and peaks near 85% on the wettest days.

0%20%40%60%80%100%151015202530
Rain chance (%)
180
280
380
480
580
680
781
881
982
1082
1183
1283
1384
1484
1585
1685
1785
1885
1985
2085
2185
2285
2385
2485
2585
2685
2785
2884
2984
3085

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 55% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202530
Oppressive (%)Miserable (%)
15149
25149
35248
45248
55347
65347
75347
85446
95446
105446
115545
125545
135545
145545
155545
165545
175545
185545
195545
205644
215644
225644
235743
245743
255842
265842
275941
286040
296139
306238

Wind in September

Winds average 14 km/h in September.

Across September, daily wind ranges from about 13 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2414light breeze
2514light breeze
2614light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

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 6:13 AM to 6:18 AM, and sunset from 6:35 PM to 6:09 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.46:136:35
212.36:146:34
312.36:146:33
412.36:146:32
512.36:146:31
612.36:146:31
712.36:146:30
812.26:156:29
912.26:156:28
1012.26:156:27
1112.26:156:26
1212.26:156:25
1312.26:156:24
1412.16:156:24
1512.16:166:23
1612.16:166:22
1712.16:166:21
1812.16:166:20
1912.06:166:19
2012.06:166:18
2112.06:176:17
2212.06:176:16
2312.06:176:16
2412.06:176:15
2511.96:176:14
2611.96:176:13
2711.96:186:12
2811.96:186:11
2911.96:186:10
3011.96:186:09

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 5.78 kWh/m².

For context, solar energy here swings from a low near 4.43 kWh/m² to a high of 6.54 kWh/m² in April across the year — September's 5.78 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.1Intense
26.1Intense
36.0Intense
46.0Intense
56.0Intense
66.0Intense
76.0Bright
86.0Bright
96.0Bright
105.9Bright
115.9Bright
125.9Bright
135.8Bright
145.8Bright
155.8Bright
165.8Bright
175.7Bright
185.7Bright
195.7Bright
205.7Bright
215.6Bright
225.6Bright
235.6Bright
245.6Bright
255.5Bright
265.5Bright
275.5Bright
285.5Bright
295.5Bright
305.5Bright
Planning a trip in September

Hazard calendar for Guayama

In seasonPeak

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

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

Guayama 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 Guayama?

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

3.9
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 Guayama.

What to pack for Guayama in September

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

In September, Guayama sees daytime highs around 28°C and nights near 25°C. Pack light clothes and rain gear. Worth having: sun protection. About 25 days see rain.

light clothesrain gearsun protection

Sea temperature near Guayama 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 offshore 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
Dec28Warm

UV index in Guayama 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 Guayama 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 Guayama 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 Guayama 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 Guayama?

Guayama sits at 18.0°N, 66.1°W, 73 m above sea level, in Puerto Rico. The nearest listed city is Cayey, 15 km away.

CaguasHumacaoGuaynaboTrujillo AltoBayamónCarolinaCandelaria

Topography around Guayama

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

Within 3 km, the terrain around Guayama has significant variations in elevation — a maximum elevation change of 396 m around an average of 80 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 901 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,308 m.

The land around Guayama is covered by trees (56%) and artificial surfaces (25%) within 3 km, trees (46%) and water (38%) within 16 km, and water (58%) and trees (33%) within 80 km.

3 km
396 m
16 km
901 m
80 km
1,308 m
treesshrubsgrasslandcroplandartificial surfaceswatermangroves
September weather nearby: Cayey 15 km · Caguas 29 km · Humacao 35 km · Guaynabo 42 km · Trujillo Alto 43 km · Bayamón 46 km · Carolina 47 km · Candelaria 48 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 Guayama (17.9841°, -66.1138°, elevation 73 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).