Daily weather brief — Guam, Thursday August 27, 2026: thunderstorms and heat, no alerts, wet Thursday then drying Saturday
TL;DR FIRST
- Beach/water: in, but watch for thunder. No marine alerts; pop-up lightning is the only real risk.
- Heat: hot. Highs mid- to upper-80s, heat index (what it feels like in the shade) pushing 98°F Thursday and Friday. Hydrate before errands.
- Rain: scattered showers and thunderstorms through Friday, 30–40% most periods, with Thursday the wettest day (half to three-quarters inch possible). Keep the umbrella in the car.
- Typhoon: none. NWS Guam/Tiyan has no active watches, warnings, or advisories for Guam.
THEN THE FULL BRIEF
No active alerts from NWS Guam/Tiyan for Guam as of Thursday morning.
Today (Thursday). Partly sunny with scattered showers and thunderstorms. High near 86°F, west-southwest wind 5–10 mph. Heat index values as high as 98°F. Rainfall between a half and three-quarters of an inch is possible — heavier than Saipan today.
Tonight. Mostly cloudy with scattered showers and thunderstorms, low around 76°F, WSW wind 5–10 mph.
2–3 day outlook. Friday stays wet — scattered thunderstorms, high 86, heat index to 98, another quarter to half inch possible. Saturday dries out a touch: mostly sunny, isolated showers, high 87. Sunday similar with 30% shower chances. Winds hold westerly at 10–15 mph through the period. No tropical system on the map.
What to do today: if you’re driving into a heavy shower, slow down — street flooding on Marine Corps Drive and Route 1 in the afternoon thunderstorms is the usual pattern. Charge the phone before you leave the house in case a cell pops up over your route.