If you’re typing san juan costa rica weather into a search bar, you’re probably looking for one of two things. You’re either headed to a specific district like San Juan de Dios or San Juan de Tibás, or you might be accidentally mixing up San Juan, Puerto Rico with San José, Costa Rica. It happens way more than you’d think. Honestly, even the airlines get it wrong sometimes.
Costa Rica doesn’t really have a "San Juan" city that functions as a major hub. Instead, it has several "San Juans" scattered around the Central Valley. These are mostly residential suburbs near the capital. Because they sit in the mountains, the weather is basically eternal spring.
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It's never truly "winter" here. You’ve got two modes: dry and green. That’s it.
What Most People Get Wrong About the Central Valley
People hear "tropics" and immediately pack for 100-degree heat and 90% humidity. If you’re heading to San Juan in the San José province, that’s a mistake. You’ll be freezing at 2 AM.
The elevation in these areas usually sits between 3,500 and 4,000 feet. At that height, the air stays crisp. While the coastal beaches are melting, San Juan stays at a comfortable $72^\circ\text{F}$ to $78^\circ\text{F}$ during the day. Locals call this the "Best Climate in the World," and they aren't even exaggerating.
The sun is brutal, though. Even if it feels cool, you're closer to the equator. You will burn in twenty minutes without realizing it.
The Two-Season Reality
Forget four seasons. In San Juan, life is dictated by the rain.
The Dry Season (Verano)
Runs from December to April. This is when the "Papagayo" winds kick in. These are fierce, dry gusts that whistle through the Central Valley. It’s the time of year when the sky is so blue it looks fake. Humidity drops. The grass turns brown. It’s the peak time for tourists, meaning everything costs more.
The Green Season (Invierno)
This starts in May and lasts through November. Don't let the word "rainy" scare you off. A typical day in San Juan during the green season starts with a gorgeous, sunny morning. You go out, grab a coffee, do your errands. Then, around 2:00 PM or 3:00 PM, the sky turns purple. It dumps rain for two hours—a total deluge—and then clears up for a cool, breezy evening.
San Juan Costa Rica Weather: A Month-by-Month Breakdown
If you want the nitty-gritty, here is how the year actually feels on the ground.
January and February
These are the windiest months. You’ll see people wearing light jackets or "chalecos." The average high is around $75^\circ\text{F}$. It’s dry. No rain. Perfect for hiking the nearby volcanoes like Irazú or Poás.
March and April
This is the "summer" peak. It’s the hottest San Juan gets. Temperatures might creep up to $82^\circ\text{F}$. Dust is everywhere because it hasn't rained in months. If you’re here during Semana Santa (Easter week), expect it to be bone-dry and bright.
May and June
The first rains arrive. The landscape turns electric green almost overnight. It's a relief, honestly. The dust settles, and the air smells like wet earth. This is a "shoulder" month where you can find great deals on rentals.
July and August
There’s a weird phenomenon called "El Veranillo de San Juan" (Little Summer of Saint John). For a couple of weeks in July, the rain just... stops. It’s a mini dry season in the middle of the wet season. It’s unpredictable, but locals love it for quick mid-year trips.
September and October
The real deal. These are the wettest months. If a hurricane is passing through the Caribbean, San Juan gets the "tail" of the storm, which means days of constant drizzle and grey skies. It’s cozy but can be frustrating if you’re trying to see the sights.
November and December
The transition. The rain starts to fade, and the "Christmas winds" begin. This is arguably the best time to visit. Everything is still lush and green from the rain, but the sun is coming back out.
Why Microclimates Matter Here
Costa Rica has about 12 different climate zones. San Juan de Tibás might be sunny while San Juan de Dios—which is higher up—is shrouded in mist.
Microclimates are real. You can drive fifteen minutes and watch the temperature drop five degrees.
If you are looking at real estate or planning a long stay, "wind" is the factor nobody talks about. Some parts of the Central Valley are in wind funnels. In January, the wind can be loud enough to keep you awake. Ask the neighbors before you sign a lease.
Practical Survival Tips for San Juan Weather
You don't need a heavy parka, but you do need a strategy.
- The Layering Rule: Wear a t-shirt for the noon sun and keep a light hoodie in your bag for the evening. When the sun goes down, the temperature drops fast.
- The 2 PM Deadline: During the green season, plan all outdoor activities for the morning. If you’re driving through the mountains in the afternoon, be ready for fog so thick you can't see your own hood.
- Footwear: Forget flip-flops if you’re walking around San Juan districts. The sidewalks are uneven, and when it rains, they turn into small rivers. Wear something with grip.
- Waterproof, not Water-resistant: If you’re buying a rain jacket, get a real one. The tropical downpours here will soak through a "water-resistant" windbreaker in seconds.
Final Actionable Steps
Check your specific destination. If your GPS says "San Juan," double-check the province. San Juan de Dios (Desamparados) is cooler and rainier than San Juan de Tibás.
Pack a high-quality umbrella—locals call them "sombrillas"—and buy it there if you have to; the ones sold in Costa Rican supermarkets are built for these storms.
Download a weather app like Windy or AccuWeather, but take them with a grain of salt. In the mountains, the only reliable forecast is looking at the peaks to the west. If they’re gone, the rain is coming.
Book your trip for May or November if you want the best balance of price and sunshine. You’ll avoid the heavy crowds of January but miss the "socked-in" grey days of October.