Guaynabo weather in August

In August, Guaynabo sees average daytime highs of 30°C and overnight lows near 25°C, with 127 mm of rain across 24 wet days and about 12.6 hours of daylight. It is the 1st-warmest and 4th-wettest month of the year here.

Day-to-day highs hold fairly steady near 30°C through the month. The sky is clear or mostly clear about 21% of the time in August, and the air most often feels oppressive.

Daylight stretches from about 12 h 48 min at the start of August to 12 h 24 min by month's end. Set against the rest of the year, August is Guaynabo's 8th-clearest and 3rd-windiest month. For the whole year in context, see Guaynabo's year-round climate.

Daytime high
30°
1st warmest
Overnight low
25°
12th coldest
Rainfall
127 mm
24 wet days
Daylight
12 h 36 min
6:10 AM – 6:47 PM
Cloud cover
63%
8th clearest
Wind
11 km/h
3rd windiest
Solar energy
6.31 kWh/m²
Travel score
3.6
out of 10

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical August day in Guaynabo reaches about 30°C in the afternoon and slips back to 25°C overnight — a 5°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, August runs on par with July and on par with September.

20°25°30°35°151015202531
Avg high (°C)Avg low (°C)
12925
23025
33025
43025
53025
63025
73025
83025
93025
103025
113025
123025
133025
143025
153025
163025
173025
183025
193025
203025
213025
222925
232925
242925
252925
263025
273025
283025
293025
303025
313025

How August really feels in Guaynabo

Once humidity and wind are folded in, August averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Guaynabo weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan26° / 22°4915.7116.0
Feb27° / 21°391311.46.2
Mar27° / 22°5514.811.96.0
Apr28° / 22°8717.712.45.3
May28° / 23°14221.912.94.2
Jun29° / 24°9920.813.14.0
Jul29° / 24°11021.8133.9
Aug30° / 25°1272412.63.6
Sep29° / 24°16825.212.13.4
Oct29° / 24°15624.911.63.6
Nov28° / 23°12422.311.14.5
Dec27° / 22°5916.510.95.8

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 28% of August, with mostly cloudy or overcast conditions the remaining 51%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15545
25545
35545
45545
55545
65545
75545
85545
95446
105446
115446
125446
135248
145347
155248
165149
174951
184951
194753
204753
214555
224456
234357
244357
254258
264258
274258
284159
294258
304159
314159

Chance of precipitation in August

Any precipitation

Guaynabo gets around 127 mm of rain over 24 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 77% and peaks near 82% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
173
273
373
473
573
673
773
873
973
1074
1174
1275
1375
1476
1577
1677
1778
1879
1980
2080
2181
2281
2382
2482
2582
2682
2782
2882
2982
3082
3182

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the oppressive band about 54% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
16238
26139
36040
46040
55941
65842
75842
85743
95743
105644
115644
125545
135545
145446
155446
165446
175347
185347
195248
205248
215149
225050
235050
245050
254951
264951
274951
284852
294852
304852
314852

Wind in August

Winds average 11 km/h in August.

Across August, daily wind ranges from about 10 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
112light breeze
212light breeze
312light breeze
412light breeze
512calm
612calm
712calm
812calm
912calm
1012calm
1112calm
1212calm
1312calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2710calm
2810calm
2910calm
3010calm
3110calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 12 h 48 min at the start of August to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 24 minutes over August. Sunrise moves from 6:05 AM to 6:13 AM, and sunset from 6:56 PM to 6:36 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
112.86:056:56
212.86:066:55
312.86:066:55
412.86:066:54
512.86:076:54
612.86:076:53
712.86:076:53
812.76:086:52
912.76:086:52
1012.76:086:51
1112.76:086:50
1212.76:096:50
1312.76:096:49
1412.76:096:49
1512.66:096:48
1612.66:106:47
1712.66:106:47
1812.66:106:46
1912.66:106:45
2012.66:116:45
2112.56:116:44
2212.56:116:43
2312.56:116:42
2412.56:126:42
2512.56:126:41
2612.56:126:40
2712.46:126:39
2812.46:126:38
2912.46:136:38
3012.46:136:37
3112.46:136:36

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.31 kWh/m².

For context, solar energy here swings from a low near 4.39 kWh/m² to a high of 6.55 kWh/m² in June across the year — August's 6.31 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.5Intense
26.5Intense
36.5Intense
46.5Intense
56.5Intense
66.4Intense
76.4Intense
86.4Intense
96.4Intense
106.4Intense
116.4Intense
126.4Intense
136.4Intense
146.3Intense
156.3Intense
166.3Intense
176.3Intense
186.3Intense
196.2Intense
206.2Intense
216.2Intense
226.2Intense
236.2Intense
246.2Intense
256.2Intense
266.2Intense
276.1Intense
286.1Intense
296.1Intense
306.1Intense
316.1Intense
Planning a trip in August

Hazard calendar for Guaynabo

In seasonPeak

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

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

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

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

Is August a good time to visit Guaynabo?

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

3.6
Sightseeing
10th-best month of the year
4.8
Beach & pool
10th-best month of the year

August is a weaker month for outdoor sightseeing in Guaynabo.

What to pack for Guaynabo in August

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

In August, Guaynabo sees daytime highs around 30°C and nights near 25°C. Pack light clothes, rain gear and sun protection. About 24 days see rain.

light clothesrain gearsun protection

Sea temperature near Guaynabo in August

The nearest coast averages about 29°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 30 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
May27Warm
Jun28Warm
Jul28Tropical
Aug29Tropical
Sep29Tropical
Oct29Tropical
Nov28Tropical
Dec27Warm

UV index in Guaynabo in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Guaynabo peaks around April 13 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 7 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highExtremeVery highApr 13UV 13Dec 16UV 7
UV index (midday)Level
Jan8Very high
Feb10Extreme
Mar12Extreme
Apr13Extreme
May11Extreme
Jun12Extreme
Jul12Extreme
Aug12Extreme
Sep12Extreme
Oct10Very high
Nov8Very high
Dec7High

Air quality in Guaynabo in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Guaynabo 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 Guaynabo?

Guaynabo sits at 18.4°N, 66.1°W, 47 m above sea level, in Puerto Rico. The nearest listed city is Bayamón, 7.0 km away.

Carolina

Topography around Guaynabo

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

Within 3 km, the terrain around Guaynabo has only modest variations in elevation — a maximum elevation change of 192 m around an average of 64 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 654 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,308 m.

The land around Guaynabo is covered by trees (51%) and artificial surfaces (45%) within 3 km, trees (54%) and artificial surfaces (28%) within 16 km, and water (61%) and trees (30%) within 80 km.

3 km
192 m
16 km
654 m
80 km
1,308 m
treesgrasslandartificial surfacesbare terrainwaterwetland
August weather nearby: Bayamón 7.0 km · Cataño 9.0 km · Trujillo Alto 11 km · Candelaria 12 km · San Juan 12 km · Levittown 13 km · Caguas 15 km · Carolina 16 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 Guaynabo (18.3575°, -66.111°, elevation 47 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).