Season by season
Dry season (December–June)
Trade winds, lower humidity and the least rain, with short showers rather than all-day downpours. The lagoon is at its clearest. This is also peak season: prices rise and hotels fill around New Year, Lunar New Year and Japan’s Golden Week.
Wet season (July–November)
Hotter, stickier and wetter, with heavy afternoon and overnight rain — though mornings are often fine and the bay stays swimmable. Hotel rates are usually lower outside the school summer holidays, and the island is at its greenest.
Sea conditions & typhoons
The reef keeps Tumon Bay calm in most conditions, but storms far out at sea can send surf over the reef and close beaches for a day or two. Typhoons are possible in any month and most likely from about August to November; hotels are built for them and will tell you what to do.
Month by month
| Month | Avg high | Avg low | Rainfall | Crowds |
|---|---|---|---|---|
| January | 30°C | 24°C | 130 mm | Very busy |
| February | 30°C | 24°C | 110 mm | Very busy |
| March | 30°C | 24°C | 70 mm | Busy |
| April | 31°C | 25°C | 80 mm | Busy |
| May | 31°C | 25°C | 110 mm | Busy |
| June | 31°C | 25°C | 165 mm | Quiet |
| July | 31°C | 25°C | 300 mm | Busy |
| August | 31°C | 24°C | 410 mm | Very busy |
| September | 31°C | 24°C | 360 mm | Quiet |
| October | 31°C | 24°C | 300 mm | Quiet |
| November | 31°C | 25°C | 210 mm | Quiet |
| December | 30°C | 24°C | 150 mm | Very busy |
Temperatures and rainfall are approximate long-term averages; individual years vary, and a single typhoon can change a month completely.
Festivals & events
- April: an international marathon and running festival usually starts and finishes around Tumon and Ypao
- Late spring–early summer: the Guam Micronesia Island Fair brings dance, crafts and food from across Micronesia to Ypao Beach Park (dates vary)
- July: Liberation Day on 21 July, Guam’s biggest holiday, with a parade in Hagåtña and a carnival season around it
- Summer: a barbecue block party has often closed part of Pale San Vitores Road for one evening (check whether it is running)
- December: hotel and street illuminations along the Tumon strip through Christmas and New Year
Our advice
For the best balance of weather and price, aim for late February to early April or late May to June, avoiding Asian holiday weeks. If you come in the wet season, plan water activities for the morning and keep an evening free to rebook an outdoor show. More detail for the whole region is on the when to go page.
