Dry season on the Pacific (December–April)
This is the classic window most first-timers picture: blue skies on the Pacific side, reliably dry days from Guanacaste down through Manuel Antonio, and the kind of beach weather that needs no backup plan. January through March is the peak — the sunniest, most predictable stretch, which is also why hotels and rental cars cost the most and book out earliest.
December and April sit on the shoulders. Early December still shows some transition weather, and late April starts to bring the first green-season showers, but both months give you nearly all the dry-season feel with slightly thinner crowds. If your dates are fixed to winter and you want the Pacific beaches, this is the window — just book lodging and flights well ahead, because everyone else has the same idea.
Green season (May–November): afternoon rain, lower prices
Don't let the name fool you — "green season" isn't a washout, it's a rhythm. Mornings are usually sunny and gorgeous, clouds build over lunch, and the rain arrives in the afternoon, often as a hard but short burst. The country turns an impossible shade of green, the waterfalls run full, and prices drop — this is when you get the deals.
The tradeoff is real: September and October are the wettest months on the Pacific coast, and some dirt roads and rural routes get rougher. But for budget travelers, surfers who don't mind rain, and anyone who prefers wildlife and empty trails over postcard sun, green season is the better trip. Plan your outdoor activities for the mornings and treat the afternoon rain as your excuse for a hammock.
The Caribbean runs its own calendar
This is the mistake I see constantly: people read "rainy season" for Costa Rica and cross out October everywhere. The Caribbean coast — Puerto Viejo, Cahuita, Tortuguero — doesn't follow the Pacific's schedule. September and October are often some of the best, drier weeks of the year on the Caribbean side, right when the Pacific is at its wettest.
The flip side: the Caribbean gets its heavy rain mid-year, roughly June and July and again around December, when the Pacific is dry. So a "bad weather month" on one coast can be a great one on the other. If your dates land in September or October, point the trip at the Caribbean. If you're stuck with a July trip, lean Pacific. The country is built for this tradeoff — use it.
Semana Santa: the one week to avoid
Semana Santa — Easter week — is the one period I'd actively steer you away from unless you genuinely love crowds. It's the biggest domestic travel week of the year: every Costa Rican family heads to the beach, hotels book out months ahead, prices spike, and the roads to the coast move at a crawl. What would normally be a two-hour drive can double.
If you can't avoid those dates, adjust: stay put in one place instead of hopping, book everything with free cancellation as early as possible, and expect beach towns to be loud and packed. Otherwise, shift one week either way and you'll pay less, drive faster, and actually get a parking spot. This applies to planning a move, too — nothing gets done that week, so don't schedule appointments or viewings.
El Niño, weather swings, and how to pick your month
El Niño and La Niña years nudge the pattern: El Niño tends to dry out the Pacific (even drier dry season, weaker green season) and can make the Caribbean wetter; La Niña flips the bias. These are tendencies, not guarantees — a "dry" Pacific in a strong El Niño still gets its afternoon showers, and forecasts beyond a couple of weeks out aren't worth building a trip around.
So here's how to actually choose: fix your dates first, then pick the coast that fits them. Winter dates → Pacific dry season. September/October → Caribbean. Shoulder months like May or November → either coast works if you accept some rain, and you'll pay less. Traveling with kids on school break → just go, and choose the coast that matches the month. The weather won't ruin your trip; arriving with the wrong expectations will.
Questions people ask
Is January really the best month to visit?
January is the most reliably sunny month on the Pacific coast, which is why everyone wants it. But it's also peak season pricing and peak crowds. If you can flex by even a few weeks into late November or early December, or into April, you'll get nearly the same weather with more breathing room.
Will it rain every day if I visit in September or October?
On the Pacific, expect afternoon rain most days — but mornings are usually fine, and it rarely rains all day. Better move: point a September or October trip at the Caribbean coast, which has one of its driest windows right then. Same country, completely different weather.
When is Costa Rica cheapest?
Green season, roughly May through November (excluding Semana Santa), brings the lowest lodging prices, and you'll often find deals without booking months ahead. September and October are the deepest discounts on the Pacific. Just remember you're trading sunshine certainty for savings.
