How we know: Sources are listed at the end. Weather figures are published climate normals; route and entry facts come from the cited pages. Wildly does not publish fare averages in prose; live prices are on the linked route pages.
Costa Rica has two seasons, not four. The dry season (roughly December–April) is when the Pacific side and the Central Valley are sunniest, and it is also when North Americans travel, so it is the high season for flights and hotels. The green season (May–November) brings afternoon rain, far fewer visitors and lower hotel rates; September and October are the wettest months on the Pacific side. The Caribbean coast runs on a different rhythm and is often at its driest in September–October.
San José weather by month
Climate normals for San José (Juan Santamaría International Airport), as published on Wikipedia's San José climate page. The Central Valley sits at about 3,800 ft, so it is milder than either coast.
| Month | Avg high | Avg low | Rain | Rain days | |---|---|---|---|---| | January | 83°F (28.2°C) | 65°F (18.5°C) | 0.2 in | 3 | | February | 84°F (29.1°C) | 66°F (18.7°C) | 0.4 in | 3 | | March | 86°F (29.9°C) | 66°F (18.8°C) | 0.5 in | 5 | | April | 87°F (30.3°C) | 66°F (19.1°C) | 3.1 in | 10 | | May | 84°F (28.8°C) | 67°F (19.2°C) | 10.5 in | 23 | | June | 83°F (28.2°C) | 66°F (19.0°C) | 11.0 in | 22 | | July | 83°F (28.2°C) | 66°F (19.0°C) | 7.1 in | 20 | | August | 83°F (28.3°C) | 66°F (18.8°C) | 10.9 in | 22 | | September | 82°F (27.8°C) | 65°F (18.3°C) | 14.0 in | 26 | | October | 81°F (27.1°C) | 65°F (18.5°C) | 13.0 in | 25 | | November | 81°F (27.2°C) | 65°F (18.3°C) | 5.3 in | 17 | | December | 82°F (27.9°C) | 65°F (18.3°C) | 1.3 in | 8 |
Temperatures barely move all year; rainfall is the whole story. December through March average under an inch a month, then May flips to more than ten inches with rain on most days, and September–October are wettest. Note the small dip in July, which locals call the veranillo, a brief drier spell in mid-summer.
Season by season
December–April (dry season, peak). Reliable sun on the Pacific coast and in the Central Valley, dusty roads in Guanacaste by March, and the busiest period for hotels, rental cars and national park entries. The two crunch points are Christmas–New Year and Semana Santa (Easter week), when Costa Ricans also travel.
May–June (early green season). Afternoon showers arrive but mornings are usually clear, the landscape turns green again and visitor numbers fall sharply. Hotels commonly publish lower green-season rates from May.
July–August (mid green season). US summer holidays bring a second, smaller wave of visitors. The July veranillo often gives the Pacific side a drier stretch, and August is turtle-nesting season at Tortuguero on the Caribbean coast.
September–October (wettest months). The quietest time of year. Some remote Pacific lodges close and unpaved roads can be difficult, but the Caribbean side (Puerto Viejo, Cahuita) is often at its sunniest. Plan mornings outdoors and keep afternoons flexible.
November (transition). Rain tapers through the month, especially after mid-November, and prices have not yet reached December levels. Thanksgiving week is the exception.
Getting there from the US
Costa Rica has two international gateways with US nonstops. San José (SJO) is the hub for the Central Valley, Arenal, Manuel Antonio and the Caribbean coast; Liberia (LIR) is the airport for the Guanacaste beaches.
According to the SJO airlines-and-destinations list, American flies nonstop from Charlotte, Dallas/Fort Worth and Miami (Chicago seasonally); Delta from Atlanta (Los Angeles seasonally); United from Houston, Newark and San Francisco with seasonal service from Chicago, Denver, Los Angeles and Washington–Dulles; JetBlue from Fort Lauderdale and New York–JFK; Southwest from Houston–Hobby and Orlando; and Alaska from Los Angeles. Liberia's list adds year-round American service from Charlotte, Dallas and Miami, Delta from Atlanta and Los Angeles, JetBlue from Fort Lauderdale and JFK, United from Houston, and a long roster of winter-only seasonal routes from cities such as Boston, Detroit, Minneapolis and Denver.
Those seasonal routes matter: many northern-city nonstops to Costa Rica run only in the dry season, so a summer trip from, say, Boston or Minneapolis usually means a connection. For today's prices see JFK to San José, Miami to San José, LAX to San José, Houston to San José and Atlanta to Liberia.
When fares tend to be lowest
Demand for Costa Rica from the US is heavily seasonal: it peaks from Christmas through spring break and Easter, has a smaller bump in July, and is quietest from late August through early November. That is when published fares are usually softest, and the same months are when green-season hotel rates apply. Fixed December dates are the hardest to buy well, so book those earlier than you would for other months.
Pick a target from the route page and set a price alert. Wildly checks the routes you track every day and emails you when the fare drops to your target.
Entry requirements for US citizens
Wikivoyage's Costa Rica page says visitors from most developed countries, including the US, can enter without a visa for up to 180 days. You need a passport valid for your stay and a return or onward ticket, which airlines check at check-in. There is a departure tax on international flights; Wikivoyage notes it is already included in the ticket price on most major airlines, including American, Delta, United, JetBlue, Southwest, Alaska and Copa. Confirm current rules with the Costa Rican embassy before you fly.
Where to go, by month
- December–April: Anywhere. Guanacaste and the Nicoya Peninsula for beaches, Manuel Antonio, Arenal and Monteverde; Corcovado in the far south is at its most accessible.
- May–August: Arenal (hot springs work in the rain), the Central Valley coffee towns, and the Pacific beaches in the morning. Tortuguero for nesting turtles from July.
- September–October: The Caribbean coast (Puerto Viejo, Cahuita) at its driest; Monteverde's cloud forest, which is atmospheric in any weather.
- November: A good time to combine Guanacaste with Arenal as roads dry out and before the holiday rush.
FAQ
What is the cheapest month to fly to Costa Rica? There is no single winner every year. The late-August to early-November stretch is usually the softest for fares because it is the wettest and quietest; check the route page for your airport and set an alert rather than relying on a rule.
Is the green season a bad time to visit? Not for most trips. Rain usually comes in the afternoon, and mornings are often clear. September and October are genuinely wet on the Pacific side, so pick the Caribbean coast or build in flexibility if you travel then.
Should I fly to San José or Liberia? Liberia if your trip is mainly Guanacaste beaches (Tamarindo, Flamingo, Papagayo). San José for Arenal, Monteverde, Manuel Antonio, the Caribbean coast or a multi-region itinerary. Both have US nonstops; Liberia has more winter-only routes.
Do US citizens need a visa for Costa Rica? No. Tourist entry is visa-free for up to 180 days with a valid passport and proof of onward travel (see Entry requirements above).
Do I need a 4WD rental car? In the dry season, a standard car handles paved routes to Arenal, Manuel Antonio and the main Guanacaste beaches. In the green season, or for Monteverde, Santa Teresa and the Osa Peninsula, higher clearance or 4WD is the safer choice.