When To Go · Destination Guide
Wrecks from two world wars, a heart shaped blue hole, and tropical walls in the Western Pacific
Updated Oct 30, 2025 • 34 sources
When to go
Guam has a dry season from January to June and a rainy season July to November.
Best overall window
Drier weather, more leeward glass offs, 27°C to 29°C water.
Outside that window
Rainier with higher typhoon risk and stronger trades.
Start with the overall answer, then switch only when scuba, freedive, snorkel, or topside timing changes the trip in a meaningful way.
The overall row stays visible so you can compare it against the currently selected scope.
| Scope | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall | Overall - Jan: Best | Overall - Feb: Best | Overall - Mar: Best | Overall - Apr: Best | Overall - May: Best | Overall - Jun: Best | Overall - Jul: Good | Overall - Aug: Tradeoffs | Overall - Sep: Tradeoffs | Overall - Oct: Tradeoffs | Overall - Nov: Tradeoffs | Overall - Dec: Good |
These do not replace the overall planner. Use them only if a specific animal or event is driving your trip dates.
Spinner Dolphins in Agat and Cocos channels
Best for Snorkel, Topside
Apr to Jul
Morning boat rides along the south coast often encounter spinner dolphins.
Sea Turtle Nesting
May to Aug
Hawksbill and green turtles nest on select beaches.
Built from climate references, access rules, and destination operators. Wildlife timing and route flexibility can shift year to year.