Guam in August | RUNGUAM, Events, Wet-Season Weather & Driving Tips

Guam Has No Public Holiday in August

Check Guam's government calendar and August is one of five months with no official holiday, alongside February, April, June, and October. That doesn't mean nothing happens, though — August is actually a month with several real, dated events on the calendar.

August falls within the August–November period when NWS Guam’s long-term climatology shows the highest concentration of tropical-cyclone activity near the island. Cyclones can occur year-round, but during this period travelers should check forecasts and Guam Homeland Security/OCD alerts frequently and keep plans flexible.

RUNGUAM Running Festival: Racing Tumon at Sunrise

August's signature event on Guam is the RUNGUAM Running Festival. RUNGUAM itself started in February 2015, founded by three runners from Guam around the idea of blending performance athletic wear with Pacific island style. Since then it has grown from an apparel brand into a running community — hosting a social running club called Run With Friends, a kids' running camp, and more, all built around the idea of growing Guam's running culture rather than just selling gear.

For the verified 2026 edition, the Guam Visitors Bureau listed August 16 as race day, with both the 5K and 10K starting on Pale San Vitores Road in front of GVB and finishing at Governor Joseph Flores Park (Ypao Beach). The official participant cap was 1,000 total — 650 for the 5K and 350 for the 10K — and the 10K included a section on the white sand of Tumon Bay. Future dates, distances and entry limits may change, so check the current official listing before planning around the race.

RUNGUAM Running Festival is held every August, but as of this writing (September 2026) the date for the next edition hasn't been announced yet. Check the official RUNGUAM site for the latest.

Village Fiesta Season Picks Up in the Central and Southern Villages

August also brings a run of village fiestas honoring patron saints in several central and southern villages. One of the most popular is the San Roque Fiesta in the central village of Barrigada. San Roque is Barrigada's patron saint, venerated as a healer, and the village observes a nine-day novena leading up to the fiesta itself. The day includes a procession carrying the saint's statue and a Mass of thanksgiving, drawing devotees from across the island who come to fulfill a promesa — a personal pledge made in exchange for a favor granted.

The same month, the port village of Piti holds a Mass and procession for the Solemnity of the Assumption of the Blessed Virgin Mary, and the southern village of Agat celebrates its Santa Rosa fiesta. According to Guampedia's official fiesta calendar, the 2026 dates fall on August 15 for both Piti and Barrigada, and August 29 for Agat.

Exact fiesta dates are set by each parish year to year and can shift, so check the Guam Visitors Bureau's official site for the current schedule before you plan a visit.

August Weather and Tropical-Cyclone Readiness: What Rental Car Drivers Should Know

August is one of Guam's wetter months. Average rainfall runs around 360mm, spread across roughly 20 rainy days, with daytime highs typically 27–31°C and humidity pushing toward 80%. Expect heat, humidity, and rain all at once.

NWS Guam’s long-term climatology shows that tropical-storm and typhoon approaches near Guam are most concentrated from August through November, with October the most active month in the historical record. August therefore marks the beginning of a higher-activity period, so travelers should monitor forecasts and official alerts closely.

One of the most destructive typhoons in Guam's recorded history makes the point. Typhoon Omar formed on August 23, 1992, and made landfall on Guam just five days later, on August 28. Landfall winds reached 195 km/h, and the storm intensified further into a super typhoon with peak sustained winds of 240 km/h. Civil defense officials estimated 75–90% of buildings on the island sustained major damage; 15 people died, and total damage came to $561 million (1992 dollars) — Guam's most destructive typhoon since Typhoon Pamela in 1976. August is a month when a storm on that scale is genuinely possible.

Guam uses a four-stage typhoon alert system called Condition of Readiness (COR). Paying attention to it while you're driving a rental car can make a real difference:

• COR4 (threat within roughly 72 hours): the baseline condition throughout typhoon season. Keep your rental's tank topped off and carry a bit more cash than usual — card payments can go down along with the power
• COR3 (roughly 48 hours out): confirm your rental company's contact number, return procedure, and what your insurance covers in a storm. Ask your hotel or the rental counter what their storm protocol looks like
• COR2 (roughly 24 hours out): skip nonessential trips and drives. Park the car somewhere sheltered — away from low-lying areas prone to flooding and away from trees that could come down
• COR1 (roughly 12 hours out): stay off the road entirely and stay indoors. Don't attempt to return or move the car until local authorities confirm it's safe

Even without a typhoon in the forecast, sudden downpours are common enough in August to cut visibility fast. Check your wipers and tires when you pick up the car, and don't push through low, flood-prone stretches of road if they're under water.

Planning to Visit Guam in August? Book Your Rental Car with Weather in Mind

Roads around Tumon get busier the weekend of the RUNGUAM Running Festival, and this is the riskiest stretch of the year for weather on top of that — so if you're renting a car in August, it's worth comparing options and booking early with an eye on each company's typhoon cancellation and change policy. Cover the safety basics, then enjoy the trip.

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