Planning a trip to Costa Rica and stressing about the weather? I get it. When I first visited back in 2018, I showed up with nothing but tank tops and got absolutely drenched in September rain. That’s why you need real local insights – not generic weather apps. Having explored every corner from Guanacaste’s bone-dry beaches to the misty Osa Peninsula jungles, I’ll break down exactly what to expect month by month. Forget textbook jargon; we’re talking real-deal advice on when to chase sun, avoid downpours, and dodge tourist crowds.
Straight Talk: You can’t cram Costa Rica temperatures into one number. Elevation swings from sea level to 12,000 feet create microclimates where mornings might require a sweater while beach zones sizzle. This guide cuts through the fluff.
Why Monthly Temperatures in Costa Rica Aren't What You Expect
Tour brochures love claiming "eternal spring," but that’s kinda misleading. While temperature ranges stay relatively consistent year-round (usually 70°F to 90°F), humidity, rainfall intensity, and regional extremes make massive differences to your experience. What really matters:
- Altitude is king: For every 1,000 ft gain, temps drop ~3.5°F. San José (3,800 ft) feels nothing like Tamarindo (sea level).
- The Pacific vs. Caribbean split: Their rainy seasons don’t align perfectly. Caribbean spots like Puerto Viejo get soaked when Guanacaste bakes.
- "Green season" isn’t just rain: It means spectacular waterfalls, cheaper prices, and empty trails – if you time showers right.
I learned this the hard way hiking Chirripó in November without proper layers. Don’t be me.
Costa Rica Temperature by Month: Complete Monthly Breakdown
Below is your cheat sheet for average Costa Rica monthly temperatures. Note: This reflects central valley averages (San José/Alajuela). Coastal and mountain areas vary wildly – we’ll dive into regional specifics later.
| Month | Avg. High (°F/°C) | Avg. Low (°F/°C) | Key Weather Notes | Crowd/Tip Alert |
|---|---|---|---|---|
| January | 79°F / 26°C | 62°F / 17°C | Peak dry season. Minimal rain, clear skies | ⭐ Busiest month. Book 6+ months ahead |
| February | 81°F / 27°C | 62°F / 17°C | Driest month. Strong Pacific winds | 🏄♂️ Prime surfing in Tamarindo |
| March | 83°F / 28°C | 63°F / 17°C | Heat builds. Last truly dry month | 🔥 Pacific coast hits 95°F+ |
| April | 84°F / 29°C | 65°F / 18°C | "Little summer" break in rains late April | 🌺 Holy Week chaos! Avoid travel |
| May | 82°F / 28°C | 66°F / 19°C | Green season starts. Afternoon downpours | 💰 Rates drop 30-50% |
| June | 80°F / 27°C | 65°F / 18°C | "Veranillo" dry spell early June | 🐢 Tortuguero nesting begins |
| July | 79°F / 26°C | 64°F / 18°C | Pacific downpours intensify | ☔️ Caribbean side driest now |
| August | 79°F / 26°C | 64°F / 18°C | Wettest Pacific month. Humid | 🚗 Roads get muddy - rent 4WD |
| September | 78°F / 26°C | 64°F / 18°C | Peak rain countrywide | ⛈️ Flooding common - check alerts |
| October | 77°F / 25°C | 64°F / 18°C | Caribbean deluges. Pacific eases | 🌧️ Many eco-lodges close |
| November | 78°F / 26°C | 63°F / 17°C | Transition month. Mornings clearer | 🌄 Best hiking weather returns |
| December | 78°F / 26°C | 63°F / 17°C | Dry season begins mid-month | 🎄 Christmas spike - book early |
What Those Numbers Actually Feel Like
Those averages hide realities. December’s 78°F in San José feels crisp at night – I always pack a fleece. But in Guanacaste, March afternoons roast at 97°F with blazing sun. Humidity is the stealth factor: Caribbean zones (Puerto Viejo/Limon) hover near 90% humidity year-round making 85°F feel like a sauna. Meanwhile, Arenal’s cloud forest at 4,000 ft might be 72°F but damp chill seeps into bones after sunset.
Regional Temperature Variations: It's Basically 4 Different Countries
Pacific Coast (Guanacaste/Puntarenas)
Dry Season (Dec-Apr): Scorching. Tamarindo/Manuel Antonio hit 95°F routinely. Ocean temps 84°F.
Rainy Season (May-Nov): Afternoon thunderstorms. August is WET. Some unpaved roads become impassable.
Local Tip: December-April needs serious sun protection. I got second-degree burns surfing in January within 90 minutes.
Caribbean Coast (Tortuguero/Puerto Viejo)
"Drier" Months (Feb-Mar & Sep-Oct): Less rain ≠ dry. Expect 80-90% humidity daily.
Wet Season (Nov-Jan & Apr-Aug): Torrential. December sees 300mm rainfall. Flooding occurs.
Temperature Reality: "Feels like" temps exceed actual by 10°F. Even 85°F feels oppressive.
Central Valley (San José/Alajuela)
Year-Round: Mild 65-80°F. Requires layers – mornings often 60°F.
Rainy Season (May-Nov): Consistent afternoon showers. Umbrella essential.
Elevation Hack: Heading to Poás Volcano? Add 20°F colder. I regretted forgetting my windbreaker last visit.
Northern Lowlands (Arenal/Monteverde)
Cloud Forests: Monteverde averages 64°F. Drizzle/mist constant. Waterproof shoes mandatory.
Volcanic Zones: Arenal sees bigger swings (58°F low to 88°F high). Evenings get chilly.
Microclimate Warning: Weather changes hourly. Pack for all scenarios in one day.
Packing for Costa Rica Temperatures: No Bullshit Checklist
Throw out "tropical packing lists" telling you to bring sundresses. After 12 trips, here’s what actually works:
- ☔ Rain Gear: Not optional. Packable rain jacket + travel umbrella (Green Season)
- 🥾 Footwear: Waterproof hiking shoes + quick-dry sandals (Keens > flip-flops)
- 🧴 Sun Defense: SPF 50 reef-safe sunscreen (expensive locally), wide-brim hat
- 🧊 Cooling Tech: Lightweight cooling towel (lifesaver in Guanacaste heat)
- 🧥 Layer Up: Fleece jacket for highlands + moisture-wicking shirts
- 🦟 Bug Warfare: DEET 30%+ for Osa/Corcovado (malaria/dengue zones)
- 🎒 Daypack Essentials: Dry bags for electronics, reusable water bottle
Pro Mistake: I once brought jeans to Tortuguero in July. They took 3 days to dry. Stick to quick-dry fabrics only.
Best Times for Activities: Matching Weather to Your Goals
Beach Hopping & Sunbathing
Prime Window: December to April (Pacific) / February-March & September (Caribbean)
Where to Target: Papagayo Peninsula (luxury resorts), Manuel Antonio (wildlife+beach combo)
Trade-off: You’ll pay peak prices and fight for sunset views at popular spots.
Wildlife Spotting
Secret Sauce: Green Season (May-Nov). Forests thicken, animals congregate at water sources.
Hotspots: Corcovado NP (June-Aug for tapirs), Tortuguero (July-Oct sea turtles nesting)
Drawback: Some trails close. I missed Cerro Chirripó summit in October due to landslides.
Surfing Conditions
Pacific: Nov-Apr (best swells) - Tamarindo for beginners, Santa Teresa advanced
Caribbean: Dec-Mar (consistent breaks) - Puerto Viejo’s Salsa Brava experts only!
Water Temp Note: Pacific averages 82°F year-round. Caribbean 79-84°F. Wetsuits rarely needed.
Hiking & Volcano Treks
Sweet Spot: Late December-February (clearest skies)
Trail Reality: Arenal/Poás often shrouded in clouds by 10am. Start at dawn.
Altitude Warning: Cerro Chirripó (12,500ft) drops below 40°F. You need thermal layers.
Costa Rica Weather FAQs: Real Answers to Actual Traveler Questions
"Is Costa Rica unbearable during rainy season?"
Not even close. Mornings are usually sunny until 1-3pm. Downpours last 2-3 hours typically. Pros: Everything’s lush green, prices drop 40%, no crowds. Cons: Some rural roads require 4WD, mosquitoes peak. I prefer May-June over December crowds.
"Which month has the best balance of sun and affordability?"
November (Pacific) or May (Caribbean). Shoulder seasons mean moderate rain, lower prices, and decent availability. Avoid Easter week – locals vacation nationwide causing logistical nightmares.
"Do I need AC everywhere given the Costa Rica monthly temperatures?"
Pacific coast? Absolutely. Central Valley? Ceiling fans usually suffice. Caribbean? Non-negotiable – humidity makes sleep impossible without AC or strong breezes. Jungle lodges often rely on natural ventilation.
"How accurate are weather apps for Costa Rica?"
Terrible. Microclimates ruin forecasts. Use them for general trends only. Better resource: Costa Rica’s Institute of Meteorology with real-time radar.
"Does 'green season' mean constant rain all day?"
Rarely. Typically intense afternoon storms followed by clear evenings. Exceptions: Caribbean in July/August gets prolonged drizzle. Osa Peninsula in September sees 24-hour downpours. Plan accordingly.
Final Thoughts: Making Your Costa Rica Temperature Decision
Obsessing over Costa Rica temperature by month? My blunt advice: Prioritize what you hate more – rain or crowds. Dry season delivers guaranteed sunshine but with premium pricing and packed national parks. Green season offers epic value and lush landscapes if you tolerate afternoon showers. Personally? I’ll take May in Osa over February in Tamarindo any day – cheaper rooms, howler monkeys in downpours are unforgettable, and empty trails feel like your private jungle. Pack smart, check regional forecasts weekly, and embrace the pura vida rhythm.
Got specific concerns about visiting in your birth month? Hit me up in the comments – I’ve probably sweated, shivered, or gotten soaked there.
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