Alajuela, Costa Rica Weather by Month: Dry Season, Rainy Season, and What to Pack

Alajuela, Costa Rica weather runs on the same two-season rhythm as the rest of Costa Rica, dry from December to April and rainy from May to November, but sitting up in the Central Valley gives it a noticeably milder feel than the beach towns.

We’re Sarah and Thomas, and we’ve lived in Costa Rica since 2016. We live near Alajuela, so we are very familiar with the weather by month. And, although we may be biased, we think the weather in this area is some of the best in the country.

We created this post to break down what to expect every month, what to pack, and when to book so you know exactly what you’re walking into.

Let’s get into it!

Dry Season (December to April)

Sunny days, cooler nights, and barely any rain. This is the easiest season for exploring Poás Volcano, coffee plantations, and Alajuela’s downtown without weather getting in the way.

Month	Daytime High	Rainfall	What to Know
December	81°F / 27°C	~1.8 in	Festive and busy, especially around the holidays
January	82°F / 28°C	<0.6 in	Peak season, dry and consistent, book ahead
February	84°F / 29°C	~0.3 in	Warm and dry, one of the driest months
March	85°F / 29°C	~0.5 in	Hottest, driest stretch, great for Poás and hiking
April	86°F / 30°C	~1.2 in	First hints of rain by month’s end

Heads up for Semana Santa: The week before and after Easter gets busy with both local and international travelers heading through the area. Book ahead if your trip lands here.

By late dry season, the landscape gets dried out. After months without rain, the hillsides around Alajuela and the wider Central Valley turn brown and dusty instead of the green you see in photos.

Also, keep in mind the mountains: When you head up into the mountains such as at Poas Volcano, expect cooler temps. I usually where pants and a long sleeve shirt with windbreaker. Also, even if it feels much cooler, the sun is still strong. Wear sun protection!

Rainy Season (May to November)

Mornings tend to be clear and sunny, with rain rolling in during the afternoon, especially early in the season. This is also when the crowds thin out, prices drop, and the whole Central Valley turns a deep green.

Month	Daytime High	Rainfall	What to Know
May	82°F / 28°C	~8 in	Rain picks up, fewer tourists
June	80°F / 27°C	~10 in	Regular afternoon showers, quiet and green
July	79°F / 26°C	~8 in	“Veranillo,” a short dry break, slight bump in visitors
August	79°F / 26°C	~11 in	Heavier rain returns, mornings often still clear
September	78°F / 26°C	~12 in	One of the wettest months, low season, good deals
October	77°F / 25°C	~17.6 in	Peak rainfall, lowest tourism, best prices of the year
November	78°F / 26°C	~9 in	Rain starts tapering off toward dry season

The rain looks different depending on when you visit. Early in the season, May and June especially, you’re mostly dealing with a predictable afternoon shower that clears out and leaves you a nice evening.

By September and October, things change. Rain can last all day, storms show up outside the usual afternoon window, and roads in and around the province are more prone to flooding.

If you want the classic sunny morning, quick afternoon rain experience, aim for May, June, or early July. If you’re coming later in the season, plan for the possibility of a full rainy day.

Keep in mind that it does cool off in the evenings and since the sun sets at 6PM it is a good idea to have long pants and a light sweater for after dark.

What to Pack

Everyday essentials

• A backpack over a suitcase if you can swing it. We use the Osprey Fairview 55L for carry-on trips (unclip the daypack for under the seat and bigger part in overhead) and the Osprey 75L when we’re checking a bag
• Sun Bum SPF 50, reef-safe and strong enough for how intense the sun gets here
• Teva Voya flip flops for men and women, waterproof with real grip
• Columbia Bora Bora sun hat, packs small and actually blocks sun
• Sun Bum Cool Down aloe lotion for when the SPF doesn’t save you
• LifeStraw Go water bottle for peace of mind, though tap water here is safe
• Insect repellent, mosquitos show up once the sun goes down year-round

Rainy season add-ons

• Anker power bank for outages
• Large ziplock bags, nothing dries in rainy season and these keep damp clothes contained
• Rain jacket, lightweight and breathable
• Motion sickness pills, helpful for winding roads
• Headlamp, useful year-round since the sun sets by 6pm

Safety Notes by Season

• Dehydration sneaks up fast in the dry season heat. Drink water and grab a Gatorade or Powerade when you feel off
• Mosquitos are worse in rainy season and can carry dengue or zika, don’t skip the bug spray, but I will say that mosquitos aren’t as bad here as in some other areas
• Heat makes hikes and activities more tiring than you’re probably used to, pace yourself. Also, the altitude can be an issue. For example. my sister gets migraines and had a very bad one at Poas, likely due to the altitude
• Rainy season brings some street flooding, land slides etc. Be cautious about driving.
• Waterfalls here often have no barriers, and rocks get slick in the rain. People have died from slipping, so use caution

Our Take

Alajuela is one of our favorite bases for exploring the Central Valley, and the weather is forgiving almost any time of year.

Dry season gives you the easiest conditions for volcano trips and coffee tours, rainy season gives you a quieter, greener version of the same city with better prices.

The one thing we’d flag either way, don’t skip sun protection just because you’re not at the beach, and if you’re visiting in the back half of rainy season, build a little flexibility into your plans in case of a full rainy day.

Ready to Plan Your Alajuela Trip?

Now that you know what to expect weather-wise, here’s where to go next.

• Want to fill your days? Check out our things to do in Alajuela guide for coffee farm tours, Poás Volcano, and everything within a 45-minute drive of downtown.
• Need a place to sleep? We break down the best hotels near San Jose airport, whether you’re crashing for one night before a flight or basing your whole trip out of Alajuela.
• Picking up wheels? Our driving in Costa Rica guide covers renting a car at San Jose airport, insurance, and what the roads are actually like, plus your 10% discount with Adobe.

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