Guaynabo, Puerto Rico experiences average highs of 30°C (86°F) and lows of 23°C (73°F) throughout the year. Rainfall is frequent, averaging about 20 rainy days per month. Sunshine is abundant, averaging about 11 hours per day. High humidity combined with warm temperatures produces a tropical feel year-round. Average highs have stayed broadly stable across the available records.
Guaynabo, Puerto Rico Weather & Climate 2026
Monthly climate averages for Guaynabo, Puerto Rico. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: May–Nov At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
4.7/10
Best: January, February, March, December
UV Index
8
High
Temperature 30°C / 23°C
Feels Like 34°C / 27°C
Rainy Days 20
Rainfall 106 mm
Sunshine 11 h
Humidity 80%
Wind Speed 15 km/h
Dew Point 23°C
Hottest Month
32°C
July
Avg Low25°C
Rain22days
Coldest Month
22°C
February
Avg High28°C
Rain15days
Driest Month
15days
February
Avg High28°C
Avg Low22°C
Windiest Month
18 km/h
July (Gusts 41)
Sea Temperature
27°C – 30°C
Warmest water: October (
30.2°C
)
Worst Time to Visit
Consider avoiding July, August, September, October due to extreme heat, heavy rainfall, oppressive humidity.
Sun Position
Sunrise 05:50
Daylight 13.2h
Sunset 19:03
Live conditions—
Guaynabo on the map · live conditions
Guaynabo, Puerto Rico
- Continent
- Americas
- Country
- Puerto Rico
- City
- Guaynabo
- Population
- 81.4K
- Elevation
- 47 m
- Coordinates
- 18.36°, -66.11°
Seasonal Breakdown
Spring
Mar–May
Avg High 30°C
Avg Low 23°C
Rain 19 days/mo
1/3 best months
Summer
Jun–Aug
Avg High 31°C
Avg Low 25°C
Rain 22 days/mo
Autumn
Sep–Nov
Avg High 30°C
Avg Low 24°C
Rain 25 days/mo
Winter
Dec–Feb
Avg High 28°C
Avg Low 22°C
Rain 16 days/mo
3/3 best months
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 28°C / 22°C . Feb: 28°C / 22°C . Mar: 29°C / 22°C . Apr: 30°C / 22°C . May: 31°C / 24°C . Jun: 31°C / 24°C . Jul: 32°C / 25°C . Aug: 32°C / 25°C . Sep: 31°C / 25°C . Oct: 30°C / 24°C . Nov: 29°C / 23°C . Dec: 28°C / 22°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 44 mm. Feb: 54 mm. Mar: 59 mm. Apr: 109 mm. May: 116 mm. Jun: 88 mm. Jul: 113 mm. Aug: 127 mm. Sep: 194 mm. Oct: 172 mm. Nov: 139 mm. Dec: 53 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 79%. Feb: 78%. Mar: 76%. Apr: 76%. May: 78%. Jun: 77%. Jul: 78%. Aug: 80%. Sep: 82%. Oct: 84%. Nov: 85%. Dec: 82%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 15 km/h . Feb: 17 km/h . Mar: 16 km/h . Apr: 15 km/h . May: 16 km/h . Jun: 17 km/h . Jul: 18 km/h . Aug: 17 km/h . Sep: 14 km/h . Oct: 13 km/h . Nov: 13 km/h . Dec: 15 km/h .
Sunshine
Sunshine
Sunshine: Jan: 10h. Feb: 11h. Mar: 11h. Apr: 11h. May: 12h. Jun: 12h. Jul: 12h. Aug: 11h. Sep: 11h. Oct: 10h. Nov: 10h. Dec: 10h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 27°C . Feb: 27°C . Mar: 27°C . Apr: 27°C . May: 28°C . Jun: 29°C . Jul: 29°C . Aug: 30°C . Sep: 30°C . Oct: 30°C . Nov: 29°C . Dec: 28°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 6. Feb: UV 7. Mar: UV 9. Apr: UV 9. May: UV 9. Jun: UV 9. Jul: UV 9. Aug: UV 9. Sep: UV 8. Oct: UV 8. Nov: UV 7. Dec: UV 6.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy
Climate Trends
Average highs have stayed broadly stable across the available records. Average rainfall is trending drier by about 19 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Aug 2025 · 32°C | Jul · 32°C |
| Coldest month | Jan 2025 · 22°C | Feb · 22°C |
| Wettest month | Sep 2025 · 226 mm | Sep · 194 mm |
| Windiest month | Jun 2025 · 19 km/h | Jul · 18 km/h |
Month-by-Month Weather Table
January best
Excellent 
February best
Excellent March best
Good April
Wet May
Wet June
Wet July
Wet August
Wet September
Wet October
Wet November
Wet December best
Wet | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January best | 28°C / 22°C | 31°C / 25°C | 16days (44 mm) Wet | 10.4h Excellent | 79% Humid | 6.4 High | Excellent | View Details |
| February best | 28°C / 22°C | 31°C / 24°C | 15days (54 mm) Wet | 10.7h Excellent | 78% Humid | 7.4 Very High | Excellent | View Details |
| March best | 29°C / 22°C | 32°C / 25°C | 17days (59 mm) Wet | 10.9h Excellent | 76% Humid | 8.5 Very High | Good | View Details |
| April | 30°C / 22°C | 33°C / 26°C | 19days (109 mm) Wet | 11.3h Excellent | 76% Humid | 8.6 Very High | Wet | View Details |
| May | 31°C / 24°C | 35°C / 28°C | 21days (116 mm) Wet | 11.5h Excellent | 78% Humid | 8.6 Very High | Wet | View Details |
| June | 31°C / 24°C | 36°C / 29°C | 20days (88 mm) Wet | 12h Excellent | 77% Humid | 8.6 Very High | Wet | View Details |
| July | 32°C / 25°C | 36°C / 29°C | 22days (113 mm) Wet | 11.7h Excellent | 78% Humid | 8.6 Very High | Wet | View Details |
| August | 32°C / 25°C | 37°C / 30°C | 23days (127 mm) Wet | 11.1h Excellent | 80% Humid | 8.7 Very High | Wet | View Details |
| September | 31°C / 25°C | 37°C / 30°C | 26days (194 mm) Wet | 10.5h Excellent | 82% Humid | 8.4 Very High | Wet | View Details |
| October | 30°C / 24°C | 36°C / 29°C | 26days (172 mm) Wet | 9.9h Good | 84% Humid | 7.5 Very High | Wet | View Details |
| November | 29°C / 23°C | 33°C / 28°C | 22days (139 mm) Wet | 9.6h Good | 85% Humid | 6.5 High | Wet | View Details |
| December best | 28°C / 22°C | 31°C / 26°C | 18days (53 mm) Wet | 10.1h Excellent | 82% Humid | 6.1 High | Wet | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Guaynabo are January, February, March, December, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Guaynabo, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Guaynabo is July, with average daytime highs of 32°C (89°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Guaynabo is February, with average overnight lows of 22°C (71°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Guaynabo is September, averaging 194mm of precipitation across 26 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Guaynabo runs through September, October, August, July, with the heaviest rainfall in September. Based on 10-year averages for Guaynabo.
Guaynabo receives approximately 130 sunshine hours per year. The sunniest month is June with around 12 hours. Based on climate data for Guaynabo.
The least favorable months to visit Guaynabo are July, August, September, October, primarily due to extreme heat, heavy rainfall, oppressive humidity. For the best conditions, consider January, February, March, December instead.
The annual average UV index in Guaynabo is 8, classified as high. SPF 30+ sunscreen, sunglasses, and seeking shade between 10:00–16:00 are strongly recommended.
Average humidity in Guaynabo is 80%, classified as humid. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in January, February, March, April, May, June, July, August, September, October, November, December average 28°C (82°F), which is warm and comfortable for swimming and water activities.
Average wind speeds in Guaynabo are 15 km/h (9 mph). The windiest month is July with peak winds reaching 18 km/h (11 mph) (gusts up to 41 km/h / 25 mph).
Guaynabo averages 1 clear-sky days per month with overall cloud cover around 55%. The clearest skies occur in January.
The annual average dew point in Guaynabo is 23°C (73°F), which feels muggy and uncomfortable. Expect heavy perspiration during warmer months — stay hydrated and take breaks in air-conditioned spaces.
Guaynabo has a Tropical Monsoon climate, classified as Am under the Köppen system. Tropical climates are warm year-round with high rainfall and temperatures rarely dropping below 18°C (64°F).
The 'feels like' temperature in Guaynabo ranges from 27°C (81°F) to 34°C (93°F) on average. Humidity and radiant heat mean it often feels warmer than the thermometer reads, especially in summer months.
June is not the best time to visit Guaynabo, with a climate score of 3.3/10. Consider visiting during January, February, March, December instead for better conditions.
For June in Guaynabo, pack Umbrella, Waterproof jacket, Waterproof shoes, Breathable clothing, Sunscreen (SPF 30+). With average highs of 31°C (89°F) and 20 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
Last updated: