Tumon in Summer
In summer (June, July and August), Tumon sees average daytime highs around 28°C and overnight lows near 26°C, with 762 mm of rain over about 78 wet days across the season. It is the warmest season of the year and the 2nd-wettest season.
Across summer, daytime highs hold fairly steady around 28°C. The sky is clear or mostly clear about 14% of the time across summer, and the air most often feels miserable.
Summer is Tumon's weakest season of the year to visit on our travel score. Tumon has little temperature swing across the year, so its calendar seasons blur — the season framing matters less here than for a place with four distinct seasons. For the whole year in context, see Tumon's year-round climate.
- Avg daytime high
- 28°C
- warmest season of the year
- Avg overnight low
- 26°C
- Rainfall
- 762 mm
- 78 wet days
- Avg wind
- 19 km/h
- Travel score
- 3.6
- weakest season of the year
- Months
- Jun · Jul · Aug
Temperature in Tumon in Summer
Across summer, daytime highs hold fairly steady around 28°C.
A typical summer day in Tumon reaches about 28°C and drops to 26°C overnight. The warmest of the three months is June, the coolest August.
How summer really feels in Tumon
Once humidity and wind are folded in, summer brings about 92 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Tumon weather by month
How the three summer months (June, July and August) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 27° / 26° | 71 | 14.7 | 11.3 | 6.0 |
| Feb | 27° / 26° | 51 | 11.3 | 11.6 | 6.3 |
| Mar | 27° / 26° | 45 | 10.2 | 11.9 | 6.7 |
| Apr | 27° / 26° | 67 | 11.1 | 12.3 | 6.5 |
| May | 28° / 27° | 81 | 15 | 12.6 | 5.6 |
| Jun | 28° / 27° | 140 | 20.4 | 12.8 | 4.4 |
| Jul | 28° / 26° | 273 | 28.4 | 12.7 | 3.3 |
| Aug | 28° / 26° | 350 | 29.2 | 12.4 | 3.2 |
| Sep | 28° / 26° | 314 | 27.2 | 12.1 | 3.3 |
| Oct | 28° / 26° | 279 | 27.5 | 11.7 | 3.6 |
| Nov | 28° / 27° | 175 | 21.5 | 11.4 | 4.5 |
| Dec | 28° / 26° | 93 | 16.8 | 11.2 | 5.6 |
Cloud cover in Summer
The sky is clear or mostly clear about 14% of the time across summer.
Chance of precipitation in Summer
Tumon gets around 762 mm of rain over 78 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels miserable — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 19 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 12 h 42 min in early June to 12 h 18 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 5.7 kWh/m².
Hazard calendar for Tumon
In summer, Tumon overlaps its pacific typhoon and monsoon season. The full year is below, with each hazard's peak months called out.
Tumon sits in the Pacific typhoon belt; the season peaks July–October.
Tumon's monsoon runs July–November, when most of the year's rain falls.
Is summer a good time to visit Tumon?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a weaker month for outdoor sightseeing in Tumon.
What to pack for Tumon in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Tumon sees daytime highs around 28°C and nights near 26°C. Pack light clothes, rain gear and sun protection. Worth having: a windbreaker. About 78 days see rain.
Sea temperature near Tumon in Summer
The nearest coast averages about 29°C across summer — the other half of the beach question. The full-year curve and swim-comfort zones are below.
The sea at the nearest coast (about 16 km away) is warmest in July at about 29°C and coldest in February near 28°C.
The water stays above 20°C all year — warm enough for a swim any month.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sea temperature (°C) | 28 | 28 | 28 | 28 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 28 |
| Comfort | Warm | Warm | Warm | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical | Tropical |
| Sea temperature (°C) | Comfort | |
|---|---|---|
| Jan | 28 | Warm |
| Feb | 28 | Warm |
| Mar | 28 | Warm |
| Apr | 28 | Tropical |
| May | 29 | Tropical |
| Jun | 29 | Tropical |
| Jul | 29 | Tropical |
| Aug | 29 | Tropical |
| Sep | 29 | Tropical |
| Oct | 29 | Tropical |
| Nov | 29 | Tropical |
| Dec | 28 | Tropical |
UV index in Tumon in Summer
Clear-sky midday UV across summer averages around 13 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Tumon peaks around August 18 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 9 (very high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 10 | 11 | 13 | 13 | 13 | 12 | 13 | 14 | 13 | 12 | 10 | 9 |
| Level | Very high | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Extreme | Very high |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 10 | Very high |
| Feb | 11 | Extreme |
| Mar | 13 | Extreme |
| Apr | 13 | Extreme |
| May | 13 | Extreme |
| Jun | 12 | Extreme |
| Jul | 13 | Extreme |
| Aug | 14 | Extreme |
| Sep | 13 | Extreme |
| Oct | 12 | Extreme |
| Nov | 10 | Extreme |
| Dec | 9 | Very high |
Where is Tumon?
Tumon sits at 13.5°N, 144.8°E, 13 m above sea level, in Guam. The nearest listed city is Tamuning-Tumon-Harmon Village, 0.0 km away.
Topography around Tumon
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Tumon.
Within 3 km, the terrain around Tumon has only modest variations in elevation — a maximum elevation change of 109 m around an average of 32 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 308 m; within 80 km, significant variations in elevation — a maximum elevation change of 387 m.
The land around Tumon is covered by water (31%), trees (25%) and artificial surfaces (23%) within 3 km, water (59%) and trees (28%) within 16 km, and water (94%) within 80 km.
Guam travel facts
- Power plugs
- Type A / B
- 110 V · 60 Hz
- GDP per capita
- $41,833
- 2022
- Safe drinking water
- 94%
- of population, 2024
- Homicide rate
- 4.3
- per 100k, 2019
- Income group
- High
- World Bank
- Religion
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 Tumon (13.4875°, 144.7814°, elevation 13 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.