September Weather in Costa Rica: A Lush Invitation to the Rainforest

The weather in Costa Rica in September—we'll be straight with you—is wet. The months of September and October are the two rainiest months of the year in Costa Rica, so if you're planning a September vacation, expect to get wet. But this isn't necessarily a bad thing. In fact, for nature lovers, it's a decidedly good thing. The rainforests glisten with raindrops that bring out all the shades of green you can imagine.

The lush landscapes are like something out of a fairy tale. Dense forests, their canopies dripping with moisture, come alive with the chirping of birds and the chatter of monkeys. September in Costa Rica allows you to experience the rainforest in its most natural and literal sense—and it's beautiful!

Costa Rica in September brings varied weather patterns. The Pacific side and Central Valley experience heavy rainfall during September, making it one of the rainiest months. On the contrary, the Caribbean coast stays relatively dry, gearing up to October—the sunniest month on that side.

In September, the Pacific beaches and central regions see frequent rain, typically with sunny mornings followed by afternoon or evening showers. Occasionally, tropical lows near the west coast or hurricanes from the Caribbean can lead to days of continuous heavy rainfall. It's worth pointing out that hurricanes virtually never hit Costa Rica directly—we're too far south. But we certainly can get lots of rain from Caribbean hurricanes.

The southern Pacific and Osa Peninsula can be hit by prolonged rain during this month caused by westerly winds, called the "temporales del Pacífico," the “Pacific storms.” When this happens, rain is measured in feet rather than inches, and many lodges and tour operators close until November. While it's not as humid as you might expect for a tropical region, it can get pretty sticky in September.

Temperatures in Costa Rica vary little throughout the year. Rain or shine, temperatures remain around the same. Expect temperatures in the 80s Fahrenheit on the coast and northern plains, 70s in the Central Valley, and late-60s in highland cloud forest areas.

If you're considering a September vacation to Costa Rica, you need to weigh up a few things regarding your personal preferences. Below, we list the main pros and cons when it comes to visiting Costa Rica this month.

September is a great time to explore Costa Rica's national parks, as the rainforest trails are less crowded. Wildlife like monkeys and sloths might be more visible, although the lush foliage can sometimes make them a bit tricky to spot. In places like Manuel Antonio, these animals aren't particularly shy, regardless of the season.

For those with whale watching on their to-do list, September is perfect. It's the prime southern humpback whale watching season, especially in Uvita and the Golfo Dulce on the Southern Pacific coast. Humpback whales gather in our warmer waters during this time as part of their breeding season, escaping the frigid waters of the Antarctic. During September, you'll find plenty of tours to get you out on the ocean to hang with these gentle giants.

September is also ideal for spotting sea turtles. Both the Pacific and Caribbean coasts offer excellent opportunities to check out nesting sites, with Olive Ridley turtles coming ashore on the Pacific side (September is peak arribada—a mass nesting event) and green turtles on the Caribbean.

Birdwatchers will also enjoy September. It's not a month to find lots of migrating species, but local hummingbirds, toucans, macaws, and more are all around and available for spotting.

September in Costa Rica is a great month for most of the activities that draw you to consider a trip to this beautiful country in the first place. Whether it's swimming, hiking, zip-lining, nature exploration, or white water rafting, you can do it all in September, no matter where you are in the country. One caveat might be with the white water rafting, where higher water levels might lead to cancellations.

It's worth noting that mornings are the prime time for action. There will be dry weather and plenty of sunshine before returning to your hotel for lunch. In the afternoons, you can unwind in a hammock as the rain gently taps on your terrace roof, creating a truly blissful experience.

And talking of bliss: these rainy afternoons are also absolutely perfect for enjoying the thermal waters of the hot springs in Arenal!

September doesn't rule out a great beach vacation in Costa Rica. Mornings often offer hot and sunny weather for quality beach and pool time. There's nothing like starting your day on the beach and winding down in a hammock in the afternoon.

Peak Pacific surfing season runs from May to October in Costa Rica. That means September is a sweet spot month for intermediate to experienced surfers looking for some of the best waves in the world. Winter storms in the South Pacific create large SW swells that particularly hit the Central and South Pacific coasts, from the bottom of the Nicoya Peninsula all the way to Panama. The rest of Guanacaste’s coastline is also good, but better for novices and those seeking lessons. Serious surfers should avoid the Caribbean side at this time—this is a calmer period there.

Looking for some sportfishing? You'll want to stick to Guanacaste in September. It's a perfect month for catching sailfish, marlin, tuna, and dorado offshore. The Caribbean side, around Tortuguero, offers great tarpon fishing in September, too. On the other hand, you should avoid the Central and Southern Pacific coasts in September.

September might be wetter but you don't need to make significant packing changes from any other time of the year. While it can be rainy, the temperature remains pretty constant. Lightweight and beach gear is still your go-to choice.

For the beach, bring your summer essentials and beachwear. You'll be comfortable in shorts and T-shirts in September. For inland areas, consider packing a light jacket or sweater for the cooler evenings. You'll also need rain gear (a light jacket or poncho), a quick-dry towel, closed-toed waterproof shoes, an umbrella, and a waterproof bag or backpack for protecting your valuables.

And don't forget your sunscreen and bug spray. Even on cloudy days, you can still get sunburned in Costa Rica. Sunscreen is expensive, so bringing your own is a good idea.

September is the Mes de la Patria in Costa Rica: "Patriotic Month." Like many of its Central American neighbors, Costa Rica celebrates its independence from Spain on September 15th, and the whole month is a celebration of this.

Wherever you are, no matter how small the community, you'll find parades and festivities going on, with local kids and community members joining together to create an Independence Day spectacle. Colorful decorations adorn the streets, and locals proudly display their national pride. Don't be afraid to join in the fun and enjoy yourself if you're in Costa Rica in September! There are various festivities during the month, but some stand out.

On September 14th, school kids gather at night on the streets near their school for the “Desfile de Faroles,” the “Lantern Parade.” Handmade paper lanterns shine all along the streets as they circle around the neighborhood and sing patriotic songs, honoring the waiting period before the independence declaration arrived in Costa Rica. On the morning of September 15th, students and adults of all ages gather on the street for the biggest event of the month, the Independence Parade. Marching bands, traditional dancers, and baton twirlers are among the main features. This parade in particular could block up some major streets depending on where you are, but they’ll usually have finished by noon. It’s all very cheery.

Visiting Costa Rica in September isn't for everyone. But if you don't mind the rain, enjoy the absence of crowds, are flexible in your plans, and seek a unique experience, it can be rewarding.

It's important to note that certain places, particularly the southern Pacific coast and Osa Peninsula (unless you're an avid surfer), are best avoided in September. Many hotels may be closed, and some activities might not be available. Instead, consider heading to the northern Pacific coast for a more reliable experience.

When traveling around the country, be prepared for potential road closures and the occasional cancellation of domestic flights due to weather. This is where the flexibility of your plans can truly pay off. With the right approach, you can still have a fantastic time in Costa Rica in September.

Costa Rica in September can produce challenges, as we've noted here. But for all the rain, you get cheaper prices, lower crowds, more space, and a lush environment with all the shades of green in the world. September is a month to enjoy the best of Costa Rica's natural wonders while still being able to catch some sun, some fish, or that perfect wave.

Speak to us about your plans and together we can decide if September in Costa Rica is ideal for you or not.