Discover the best time of year, based on historical climate, temperature, and precipitation.
The best weather in Guam is from January, February, March. — consistent weather climate
⛈Hot & rainy
| Score | 79 | 81 | 78 | 72 | 63 | 57 | 42 | 38 | 38 | 42 | 57 | 74 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Climate | Hot & dry | Hot & dry | Hot & dry | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy | Hot & rainy |
| Temperature | 25–29°C | 25–29°C | 25–29°C | 25–29°C | 26–30°C | 25–30°C | 25–30°C | 25–29°C | 25–29°C | 25–29°C | 25–30°C | 25–29°C |
| Feels like | 27–31°C | 27–31°C | 28–33°C | 28–34°C | 29–35°C | 30–35°C | 30–35°C | 29–35°C | 29–35°C | 29–34°C | 29–34°C | 28–32°C |
| Precipitation | 95mm 19 days | 70mm 14 days | 84mm 17 days | 119mm 20 days | 154mm 21 days | 172mm 25 days | 368mm 30 days | 512mm 30 days | 489mm 30 days | 453mm 30 days | 194mm 26 days | 128mm 21 days |
| Sunshine | 10.1h ☀︎ 89% | 9.9h ☀︎ 85% | 10.9h ☀︎ 90% | 11.3h ☀︎ 91% | 11.4h ☀︎ 89% | 10.9h ☀︎ 85% | 7.1h ☀︎ 55% | 5.4h ☀︎ 43% | 5.7h ☀︎ 46% | 6.2h ☀︎ 52% | 9.8h ☀︎ 86% | 10.4h ☀︎ 92% |
| Wind | E · 23 km/h | E · 25 km/h | E · 21 km/h | E · 21 km/h | E · 20 km/h | E · 18 km/h | E · 17 km/h | SE · 17 km/h | SE · 17 km/h | E · 18 km/h | E · 22 km/h | E · 25 km/h |
| Humidity (%) | 79% | 76% | 78% | 80% | 80% | 82% | 86% | 88% | 87% | 88% | 83% | 80% |
| Day length | 11.4h | 11.7h | 12.1h | 12.4h | 12.7h | 12.9h | 12.8h | 12.6h | 12.2h | 11.8h | 11.5h | 11.3h |
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A standard weather chart points you toward February, but April is Guam's true sweet spot: the winter tour crowds have vanished, the days deliver over eleven hours of fierce tropical sunshine, and the island settles into a quiet, sun-baked rhythm before the heavy wet season takes hold.
Guam is the southernmost and largest outpost of the Mariana Islands, an isolated ribbon of coral reef, limestone plateau, and volcanic ridge rising out of the western Pacific. It sits closer to Manila and Tokyo than to Honolulu, bearing 3,500 years of Chamorro heritage overlaid with deep layers of Spanish missions, wartime wreckage, and modern American infrastructure. Most travelers who fly into the international airport at Tamuning head straight for the protected reef flats of Tumon, but when you arrive changes everything about what you find. The travel industry treats the dry months of early winter as peak perfection, yet the island is never more rewarding, spacious, or deeply itself than in the fleeting calm of mid-spring.
If you follow standard travel advice, you will book February and spend your trip sharing the sands of Tumon Bay with tour buses and packed resort lobbies. If you look at the island's rhythm instead, April is the masterstroke. While the air registers in the low thirties with noticeable tropical humidity, the winter rush has emptied out, giving you room to breathe. The daily cloud cover stays light, the skies reliably offer over eleven hours of sunshine, and the ocean is calm and glassy.
April also hosts the Guam International Marathon, when runners line up in the pre-dawn dark along the coastal road to Hagåtña before the morning sun heats the asphalt. The pace across the island slows down noticeably after the race crowds depart, leaving the beaches south toward Agat and the scenic overlooks empty.
May begins the slow tilt toward the wetter half of the year, but it remains one of the most culturally vibrant months to explore beyond the hotel strips. The village of Agat celebrates its annual Agat Mango Festival with backyard pride, serving everything pickled, stewed, and fresh from local groves. Around the same time, the Guam Micronesia Island Fair gathers seafaring delegations, carvers, and dancers from across the neighboring archipelagos, while the southern hamlet of Malojloj opens its homes and church grounds for the Malojloj Fiesta honoring San Isidro Labrador. You will encounter passing afternoon showers, but they are quick, warm interruptions rather than trip-wrecking downpours.
June presents the great contradiction of Guam travel: it is statistically the most crowded month of the entire year, yet the weather is demonstrably sliding backward. School vacations across East Asia send waves of travelers into Tumon, filling the shallow waters with paddleboards and snorkeling gear just as the moisture index begins to spike. The heat index routinely sits in the mid-thirties, and the air turns thick and motionless between rain squalls.
By July, the atmosphere breaks open. Rainfall totals more than double from June, dumping heavy water across the southern hills. Tropical disturbances brewing in the Mariana basin begin to drift across the island, turning afternoon swims into indoor waiting games. Sunshine drops noticeably as persistent cloud decks roll in off the Philippine Sea.
Yet July holds the emotional center of the Chamorro calendar. Liberation Day on July 21 marks the 1944 amphibious landing that ended the brutal wartime occupation. The parade down Marine Corps Drive through Hagåtña is a massive, island-wide gathering of marching bands, village floats, and all-day barbecues fragrant with smoke from red rice and chicken kelaguen. If you come in July, come for the profound community spirit and civic remembrance, but do not expect a dry beach holiday.
From August through October, Guam experiences the full brunt of the western Pacific monsoon. Rainfall amounts exceed 450 to 500 millimeters each month, delivered not as romantic tropical drizzles but as violent, sustained downpours that swamp roads, turn red dirt hiking trails into impassable slides, and cloud the coastal visibility down to zero.
September and October bring the lowest visitor numbers of the year, and it is easy to see why. The apparent temperature remains stifling, the sun is throttled down to five or six hours a day, and the risk of typhoons tracking through the Mariana chain requires keeping a daily eye on weather advisories. The Ko'ko' Road Race takes place in October, with runners tackling the coastal course through heavy, moisture-laden predawn air, testing endurance against extreme humidity.
This is not a period for casual leisure travel. If you visit in early autumn, plan around indoor museum visits in Hagåtña, local village bakeries, and the unpredictable windows of sunshine between squalls. When the weather does clear for an afternoon, the jungle interior south of Dededo is lush and brilliant emerald, but the next thunderstorm is never far behind.
November is the transitional hinge where the western Pacific trade winds begin to reassert control. The staggering monsoon rainfalls drop by more than half, humidity moderates slightly, and sunshine climbs back toward ten hours a day. The ocean clears, drawing divers back to the reef walls and outer drop-offs.
December opens the dry season proper. The apparent temperature settles into the lower thirties, tempered by continuous sea breezes that make outdoor evenings comfortable. Village decorations appear across Dededo and Hagåtña, blending traditional nativity displays with woven palm fronds.
New Year's Eve transforms Tumon Bay into a natural amphitheater, where thousands of residents and travelers gather along the pale sand to watch synchronized fireworks bloom over the water. The island feels bright, breezy, and alive, though crowd numbers surge rapidly as winter holidays get underway in the northern hemisphere.
January, February, and March provide the classic postcard climate: low rainfall, brisk trade winds, and water clarity that stretches fifty feet down across the coral gardens. February delivers the driest air and the absolute best weather metrics of the entire year, with minimal rainfall and mild overnight breezes.
Because this window is so dependable, you will share it with everyone else. Flights arrive full, car rentals sell out, and popular spots along Tumon Bay buzz with constant tour activity. Hagåtña's historical plazas see continuous foot traffic, and peaceful solitude along the northern cliff lines is hard to come by.
If perfect conditions with zero rain risk are your only requirement, February justifies the premium. But if you want that same luminous blue water and sunny sky without the wall-to-wall crowds, hold out just a few weeks longer for the April window.