Costa Rica has two main seasons rather than four, and the right time to visit depends on what you value most: the clearest views, the lushest scenery, the lowest prices or the smallest crowds. San José and Arenal share the pattern but differ in details, so it helps to understand both before you book.
The dry season
Roughly from December to April, the Central Valley and the Arenal area are at their sunniest. Mornings are usually clear, the volcano is most often visible and roads and trails are in the best condition. This is also high season, so hotels cost more, popular tours sell out and the hot-springs resorts fill up, especially around Christmas, New Year and Easter. If you want to be sure of dry walking weather, this is the safe choice, but book hotels and activities well ahead.
The green season
From about May to November, afternoon rain is typical, often arriving after a sunny morning. The forest is lush, rivers and waterfalls are full and the countryside glows. Prices are lower, crowds are thinner and many activities are easy to book at short notice. Plan outdoor sights for the morning and keep the afternoons for museums, spas, hot springs and long lunches. Arenal receives rain in any month because it sits on the Caribbean-influenced side of the mountains, so a rain jacket belongs in your bag whatever the season.
Shoulder months
The edges of the green season, roughly May to June and the later months toward the start of the dry season, can be the sweet spot: green scenery, fewer people and still plenty of sunshine in the mornings. The wettest stretch tends to come in the middle of the green season, when roads can be slower and some trails muddier, so build in a spare day if your schedule is tight. If you are flexible, ask hotels about packages and free-night offers in these months, because they are often easier to find when occupancy is lower.
San José versus Arenal
The capital sits high in the Central Valley, so it is mild all year, with comfortable days and cool nights. Arenal is lower, warmer and wetter, with a rainforest climate. Volcano views depend on cloud, and it is common for the summit to be hidden by midday in any season. If seeing the cone matters, plan your volcano hike for the first morning and keep a second morning in reserve.
Activities by season
The waterfall and Río Celeste are most dramatic when the rivers are full, although the Río Celeste is most vividly blue after a few dry days. Hot springs are wonderful in any weather, and they feel best in the cool, wet evenings of the green season. Birdwatching and wildlife walks are good year-round, and migrant birds add variety in the cooler months. Rafting is available all year, but river levels change the character of the rapids, so ask the operator what to expect.
Crowds and prices
Costa Rica also has local holiday peaks, including Christmas, the weeks around Easter and school holidays, when Costa Ricans travel too and popular places are busy. Outside these, you can often find good rates in the green season, especially at larger resorts. If you are travelling with children, school holidays in your own country may drive your choice, so book early whichever season you choose.
How to decide
Choose the dry season if you want maximum sunshine and the clearest volcano views and do not mind paying more. Choose the green season if you want lush scenery, lower prices and quieter sights, and are happy to plan around afternoon rain. Choose a shoulder month if you want a balance. Whichever you pick, pack layers, a rain jacket, sun protection and closed shoes, and start your outdoor days early.
Mix and match by interest
Birdwatchers and photographers often prefer the early dry season, when forests are still green and skies are clear. Hikers who do not mind mud will enjoy the quiet trails of the green season. Hot-spring lovers can go at any time, and travellers focused on the capital’s museums and theatres will find San José pleasant all year, since the Central Valley rarely feels hot. Think about what you want your best photograph to be, and plan your dates around it.
Weather planning tips
Check forecasts the evening before big outdoor days, keep one flexible day for weather, and pick activities that can be done in light rain, such as hanging bridges, hot springs, night walks and the museums in San José. For driving, avoid mountain roads after dark in any season.
