Weather in Guam - today, tomorrow and 14-day forecast

Right now temperatures across Guam range from 28° to 29°. Below: today's conditions city by city, a live weather map, the 14-day outlook and month-by-month climate to help you pick the best time to travel.

Country values are the median of forecasts from 4 cities; the range shows local differences. Methodology.

Weather in Guam's cities today

🌧️Dededo 29°💧 5.4 mm 🌧️Tamuning 29°💧 5.6 mm 🌧️Mangilao 29°💧 5.2 mm 🌧️Yigo 28°💧 5.4 mm

Weather map - today's temperatures

Pill colour shows today's daytime temperature. Click a city for its full 14-day forecast.

Next days in Guam

today🌧️ 29°💧 5.4 mm

Sun🌧️ 28°💧 6.8 mm

Mon☁️ 28°💧 0.6 mm

Tue☁️ 28°💧 0.3 mm

Wed🌧️ 28°💧 0.6 mm

Thu🌧️ 28°💧 5.6 mm

Fri🌧️ 28°💧 2.7 mm

Sat🌧️ 28°💧 5.8 mm

Forecast vs 1991-2020 climate normal

How does the current forecast compare with normal?

We compare the coming days with weather usually observed at this time of year.

NASA POWER

Monday 7 Sept in Guam, the forecast high is 28°C. Typical daytime temperatures at this time of year range from 28°C to 29°C, so it will be exceptionally cool. It is cooler than 95% of similar days.

Saturday 5 Sept

29°Cwarmer than usual

usually 28°C–29°C

warmer than 70% of similar days

night: exceptionally cool rain: typical rainfall wind: lighter than usual

Sunday 6 Sept

28°Ccooler than usual

usually 28°C–29°C

cooler than 77% of similar days

night: exceptionally cool rain: typical rainfall wind: typical

Monday 7 Sept

28°Cexceptionally cool

usually 28°C–29°C

cooler than 95% of similar days

night: exceptionally cool rain: exceptionally dry wind: typical

Tuesday 8 Sept

28°Ccooler than usual

usually 28°C–29°C

cooler than 78% of similar days

night: exceptionally cool rain: exceptionally dry wind: typical

Wednesday 9 Sept

28°Ccooler than usual

usually 28°C–29°C

cooler than 76% of similar days

night: exceptionally cool rain: exceptionally dry wind: typical

Thursday 10 Sept

28°Ccooler than usual

usually 28°C–29°C

cooler than 72% of similar days

night: exceptionally cool rain: typical rainfall wind: typical

Friday 11 Sept

28°Cnear normal

usually 28°C–29°C

night: exceptionally cool rain: less rain than usual wind: lighter than usual

How warm was this week in previous years?

Each bar shows the average daily high during the same 7-day period in each year.

swipe to see more years →

cooler yearstypical rangewarmer years2026 forecastcurrent forecast

From 1981 to 2025, the 5-11 Sept period averaged 29°C by day. The coolest year was 2004 (28°C) and the warmest was 2024 (30°C). The current forecast averages 28°C - lower than in 71% of historical years.

Historical reference: NASA POWER daily gridded data (MERRA-2), the 1991-2020 normal and a +/- 7-day calendar window. The typical range is the 20th-80th percentile. This is not a city weather-station reading and does not change the current forecast. NASA POWER Daily API.

14-day forecast - Guam

Guam - 14-day weather forecast infographic

Guam 30 & 45-day weather - long-range outlook

Next 16 days · forecast

28°

around 26° at night · days with rain: 8

Weeks 3-4 · avg for September

31°

around 25° at night · rain chance 83%

Weeks 5-7 · avg for October

31°

around 25° at night · rain chance 80%

The 30 & 45-day outlook for Guam: the next 16 days are a numerical forecast updated daily - on average 28° by day and 26° at night. Further out we rely on multi-year climate averages: around 31° in September, and about 31° in October. Forecasts beyond two weeks are indicative only.

Today vs the next days - Guam cities

City	Today	+3 days	+7 days	Rain today
🌧️ Dededo	29℃	28℃	28℃	5.4 mm
🌧️ Tamuning	29℃	29℃	29℃	5.6 mm
🌧️ Mangilao	29℃	29℃	28℃	5.2 mm
🌧️ Yigo	28℃	27℃	28℃	5.4 mm

Day-by-day forecast for Guam

Saturday5 September 2026

🌧️29°moderate rain

night 25° · evening 26° · rain 5.43 mm · humidity 77% · wind 4 m/s · clouds 81%

Sunday6 September 2026

🌧️28°moderate rain

night 26° · evening 26° · rain 6.775 mm · humidity 76.5% · wind 5 m/s · clouds 99.5%

Monday7 September 2026

☁️28°overcast clouds

night 26° · evening 27° · rain 0.63 mm · humidity 74.5% · wind 5 m/s · clouds 88%

Tuesday8 September 2026

☁️28°broken clouds

night 26° · evening 27° · rain 0.29000000000000004 mm · humidity 76.5% · wind 5 m/s · clouds 81%

Wednesday9 September 2026

🌧️28°light rain

night 27° · evening 27° · rain 0.5800000000000001 mm · humidity 77.5% · wind 5 m/s · clouds 91.5%

Thursday10 September 2026

🌧️28°light rain

night 27° · evening 26° · rain 5.6 mm · humidity 78.5% · wind 5 m/s · clouds 83.5%

Friday11 September 2026

🌧️28°light rain

night 26° · evening 26° · rain 2.745 mm · humidity 74.5% · wind 5 m/s · clouds 93.5%

Saturday12 September 2026

🌧️28°light rain

night 27° · evening 27° · rain 5.82 mm · humidity 71.5% · wind 4 m/s · clouds 80%

Sunday13 September 2026

🌧️29°light rain

night 27° · evening 27° · rain 2.685 mm · humidity 77% · wind 5 m/s · clouds 65%

Monday14 September 2026

🌧️29°light rain

night 27° · evening 27° · rain 0.9450000000000001 mm · humidity 78% · wind 6 m/s · clouds 100%

Tuesday15 September 2026

☀️29°clear sky

night 27° · evening 27° · rain 0.46499999999999997 mm · humidity 75% · wind 4 m/s · clouds 5.5%

Wednesday16 September 2026

🌧️29°light rain

night 27° · evening 28° · rain 0.72 mm · humidity 71% · wind 2 m/s · clouds 24.5%

Thursday17 September 2026

🌧️29°light rain

night 27° · evening 28° · rain 0.5549999999999999 mm · humidity 71.5% · wind 2 m/s · clouds 70.5%

Friday18 September 2026

☀️29°clear sky

night 26° · evening 27° · rain 6.0600000000000005 mm · humidity 69% · wind 3 m/s · clouds 2.5%

Saturday19 September 2026

☀️28°clear sky

night 26° · evening 27° · rain 2.115 mm · humidity 74.5% · wind 4 m/s · clouds 15%

Sunday20 September 2026

☀️28°clear sky

night 26° · evening 27° · humidity 76% · wind 5 m/s · clouds 1%

Sea temperature - Guam

Water today

29°C

Week avg

30°C

Waves today

1 m

How's the water?

very warm

16-day sea temperature forecast:

5.09 29°C6.09 30°C7.09 30°C8.09 30°C9.09 30°C10.09 30°C11.09 30°C12.09 30°C13.09 30°C

Average sea temperature through the year:

Jan 29°CFeb 28°CMar 28°CApr 29°CMay 29°CJun 30°CJul 30°CAug 30°CSep 30°COct 30°CNov 30°CDec 29°C

Beach	Water today	Water week avg	Waves	How's the water?
Dededo	29℃	30℃	1 m	very warm
Yigo	29℃	30℃	1 m	very warm
Tamuning	29℃	30℃	1 m	very warm
Mangilao	29℃	30℃	1 m	very warm

Sea-surface temperature from marine models, updated daily. See also: where the sea is warmest right now.

Guam weather through the year

Guam weather month by month - when is the best time to go?

January (30°)February (30°)March (31°)April (31°)May (32°)June (32°)July (31°)August (31°)September (31°)October (31°)November (32°)December (31°)

Weather in other countries in Oceania

KiribatiFrench PolynesiaMarshall IslandsFijiFederated States of MicronesiaCook Islands

FAQ - Guam weather

What is the weather like in Guam today?

Today it is about 29° during the day and 25° at night, moderate rain.

How far ahead can I check the forecast for Guam?

This page shows a detailed 14-day forecast plus the long-term monthly climate, so you can plan both a short trip and a holiday months ahead.