Season by season
Dry season (December–June)
The drier half of the year, but not the calmest: strong north-east trade winds raise a steep swell through the winter months, making passages uncomfortable and beach landings difficult. Conditions often ease from about April, and the calmest seas tend to come between April and June — though nothing is guaranteed this far out.
Wet season (July–November)
More rain, more humidity and lighter winds between weather systems, so there can be windows of flat water. This is also the heart of the typhoon season, and a vessel several days from port has little room to run. Most voyages avoid the later months.
Sea conditions & typhoons
There are no harbours, so every landing is over an open beach or rock shelf and depends on the swell on the day. Typhoons are possible in any month and likeliest from about August to November. Volcanic activity is a separate risk: an eruption or a rise in unrest can close an island and the airspace above it with little warning.
Month by month
| Month | Avg high | Avg low | Rainfall | Crowds |
|---|---|---|---|---|
| January | 29°C | 23°C | 95 mm | Quiet |
| February | 29°C | 23°C | 70 mm | Quiet |
| March | 30°C | 23°C | 60 mm | Quiet |
| April | 31°C | 24°C | 65 mm | Quiet |
| May | 31°C | 25°C | 85 mm | Quiet |
| June | 31°C | 25°C | 125 mm | Quiet |
| July | 31°C | 25°C | 215 mm | Quiet |
| August | 31°C | 24°C | 320 mm | Quiet |
| September | 31°C | 24°C | 290 mm | Quiet |
| October | 31°C | 24°C | 270 mm | Quiet |
| November | 30°C | 24°C | 160 mm | Quiet |
| December | 29°C | 24°C | 110 mm | Quiet |
Temperatures and rainfall are approximate long-term averages; individual years vary, and a single typhoon can change a month completely.
Festivals & events
- January: the Marianas Trench Marine National Monument was proclaimed in January 2009
- April–June: often the calmest seas of the year, and the usual window for the few voyages that go north (conditions vary)
- May: the anniversary of Anatahan’s first recorded eruption, in May 2003; Mount Pagan’s major eruption was in May 1981
- August–November: the likeliest months for typhoons, when very few vessels venture north
Our advice
If you are seriously planning a voyage, aim for April to June, allow spare days at both ends and accept that the weather may send you home without a landing. If you are simply curious, any time of year will do: the clearest long views from northern Saipan usually come in the dry season. Regional weather is covered on the when to go page.
