San Blas Weather Month by Month: Rain, Sea and Crowds

San Blas has two seasons. The dry season runs from December to April, with January to March the most reliable stretch for clear skies; the green season runs from May to November, with short, heavy showers rather than all-day rain. The sea is warm in every month and boats leave Cartí every day of the year.

How to read this month-by-month table

The table below describes tendencies, not promises. We do not publish rainfall figures for each month because we do not have a reliable station record for the islands themselves, and invented precision is worse than none. What follows is the pattern that shapes trips on the water, written to match our best time to visit guide, which covers the choice between the two seasons in more depth.

Month	Rain	Sky and sea	Crowds
January	Rare	Clear, sunny and breezy	High
February	Rare	Clear and breezy	High, peaking around Carnival
March	Rare	Often the clearest light of the year	High, very busy around Holy Week
April	Occasional, returning late in the month	Mostly clear, hotter, wind easing	Busy if Holy Week falls in April
May	Showers begin	Sunny mornings, greener islands	Low
June	Regular short showers	Calm, warm, green	Low
July	Regular short showers	Warm and green	Low to moderate, some northern holidays
August	Regular short showers	Warm and green	Low to moderate
September	Regular short showers	Warm; calm days are common	Low
October	Regular short showers	Calm water between showers	Low
November	Regular, easing late in the month	Green, warm	Busy around Panama’s national holidays
December	Tapering off	Clearing, wind picking up	Very busy from mid-December

Dry season, December to April

The dry season is shaped by the trade winds. Skies clear, the light turns the shallows that bright turquoise, and rain becomes the exception. The wind keeps the heat comfortable on the islands and can make the open-water runs livelier on breezy days, which matters more on a long route such as Cayos Holandeses than on the short hops near Cartí. March is often the favourite of photographers: the dry season has settled and the light is at its steadiest.

The cost is company. These are high-season months across Panama, and the busiest weeks are set by the calendar rather than the weather: Christmas and New Year, Carnival in February or early March, and Holy Week in March or April. If you need one specific date in this stretch, book it early.

Green season, May to November

Rain here rarely means a grey, wasted day. The usual pattern is a hard shower that passes, often within half an hour, followed by sun. Mornings are frequently clear, the islands are at their greenest and the water is as warm as it is in February. The archipelago is noticeably quieter, which for many travellers is the whole point.

What a shower looks like from a boat or a cay is worth picturing before you book. The sky darkens over the mainland mountains first, the captain heads for the nearest island or waits it out under a palm roof, and twenty minutes later people are back in the water. Phones and cameras need a dry bag; swimmers barely notice, because the rain is warm. The real cost of the green season is the occasional grey hour in your photographs, not a lost day.

Two periods break the calm. July and August can bring some northern-hemisphere holiday traffic, and November is Panama’s month of national holidays, when domestic travellers head for the coast. Outside those weeks, May, June, September and October are the emptiest months of the year.

What changes with the calendar besides the weather

• Lobster. It is off the menu from 1 March to 30 June, when the Guna and national closed seasons overlap. We explain the rules in what you eat in San Blas.
• Booking pressure. Dry-season weekends and holiday weeks sell out first; green-season dates are usually easier to get.
• Light for photos. More dependable from January to March; more dramatic, with clouds and greener islands, from May to November.
• What stays the same. Water temperature, departure times and the routes themselves. A day trip still leaves Panama City around 5:00 AM in every month.

Storms, cancellations and forecasts

Panama lies south of the usual track of Caribbean hurricanes, so direct hits are rare; the weather that interrupts San Blas is local — a squall, a windy morning, a rough patch of sea. Tours are cancelled only when the crossing is genuinely unsafe, and in that case the operator reschedules or refunds in full. Ordinary rain cancels nothing.

For the days around your trip, the most useful source is the forecast from Panama’s meteorological institute, IMHPA, checked a few days out. A forecast says more about your Tuesday than any monthly average.

Which month should you choose?

• For clear skies and photos: January to March.
• For empty islands at a lower season: May, June, September or October.
• For a family trip with school holidays: July or August, accepting some showers.
• For an overnight stay: any month; a night on an island is good in rain or shine, and our overnight stays guide explains what changes. Pack a light rain layer either way, as listed in what to pack.

Frequently asked questions

What is the rainiest time of year in San Blas?

The green season, from May to November, brings most of the rain, usually as short, heavy showers. Rainfall varies from year to year, so check IMHPA’s forecast a few days before your trip rather than relying on a monthly average.

Is there a hurricane season in San Blas?

Panama sits south of the usual hurricane tracks, so direct hits are rare. The weather that affects trips is local wind and sea, and tours run unless the crossing is genuinely unsafe.

Is the sea warm all year?

Yes. The water stays warm in every month, so swimming and snorkelling are possible year-round. What changes between seasons is the sky and the number of people, not the sea temperature.

When is San Blas least crowded?

May, June, September and October are usually the quietest months. The busiest periods are Christmas and New Year, Carnival, Holy Week and Panama’s national holidays in November.

Is December a good month to visit?

Yes, with a caveat. Rain tapers off and the skies clear through the month, but from mid-December the holiday season makes it one of the busiest times of the year, so book early.