I'm thinking in terms of the drier part of the year, from roughly November (which still seems to be pretty wet) through February or maybe March. From the info I've looked at, it looks like December gets less days with rain, but still a significant number. January is drier, but seems to be the peak of the high tourist season -- Road Scholar runs roughly 20 tours in January alone, departing about every other day. Would that be a disadvantage?

Or are the showers generally so short that this isn't that important a consideration?

I have no Costa Rica experience but figure your question answer may be similar to visiting Mexico. Yes the drier less hot months are Dec thru April. That also means 'high season' for tourists. Prices drop a bit May thru October but you likely encounter less ideal weather.

As far as duration of rain... I've seen "monsoon" style storms blow thru and only last one evening but truly significant. I've had trips that were perfectly dry and beautiful in the same month where another trip I ran into 5-straight days of rain (unusual but it can happen).

Just sayin' you never know

Suze's post isn't terribly helpful, since, as she admits, she's never been to Costa Rica and only has been to 1 place in Mexico, a coastal area, so not sure how that relates to the entirety of Costa Rica. Costa Rica's climate can vary widely, depending on where you're going; you don't specify. Our trip was in February, it was raining in San Jose, although lightly, upon our arrival. Atenas was warm & dry. Manuel Antonio & Jaco were brutally hot & humid even in February. Arenal was misty at times, but not rainy. Hopefully Jeff & volcano girl can chime in. I didn't find our trip to be terribly touristy. Although we rented a car thus didn't have to depend on tours.

I went in late Jan and didn’t mind the crowds at all - dry weather made everything easier, and most rain (when it happened) was just short afternoon showers.

We traveled in Costa Rica in mid-December, 2019, and found it to be very rainy in the mountains, and mostly dry and warm along the Pacific coast. We stayed in La Fortuna in the mountains - very much enjoyed the hot springs and we also hiked. The rains were not cold at all, but there were some pretty major downpours. We stayed in Tamarindo and near Manual Antonio Park while at the coast - both were really wonderful. Beaches are beautiful, and temperatures perfect. There was one very impressive thunderstorm while we were at Manuel Antonio. Great river rafting in both the mountains and near Manuel Antonio.

We rented a car and took a lot of backroads. Great two-week adventure.

Thank you for the responses so far!

We would be traveling on a Road Scholar itinerary that commences in San Jose (but not for long), then continues to Sarapiqui, then to Tortiguero on the Caribbean coast, then to the Arenal area, and finally I believe to Manuel Antonio Park on the Pacific coast before returning to and flying home from San Jose. A total of 12 days.

That sounds as if you will see a lot of the country - but also a lot of the inside of a bus and your fellow tour-mates. If you are at all open to independent travel, I would recommend it. Costa Rica is very easy to navigate.

Good to hear! However, while I was committed to arranging my own trips for most of my life, now that I am retired, I find that an experienced tour company that visits a country often will do a superb job of identifying excellent restaurants and hotel options, and can do so at a price that as a solo traveler, it would be difficult for me to match. Another advantage of group travel that I had overlooked is the sheer pleasure of the comaraderie with the other members of the group, who (at least with the right company) are typically interesting, curious people who are exceptionally well-traveled themselves. (On my last group trip, one of the members of the group of 11 has sailed through the Northwest Passage north of Canada once in each direction -- among numerous other adventures!). So they can be an excellent source of future travel intel, or of companionship on a future trip when you have similar interests and are in a position to make your schedules jibe.

Of course, group travel imposes costs in terms of a loss of flexibility and spontaneity. You can't ask a bus driver to stop whenever you want to take a photograph of some passing scene (although I have become sufficiently adept at the photographic sub-field of "shooting through train or bus windows" that this isn't as much of a problem as it used to be). And you may have to forego sites that are of great interest to you, but not to many others. Even there, however, some personal time is often built into group travel. On my last group trip, for example, I twice excused myself from group activities so that I could do something that had a special appeal for me where I was in a position to rendezvous with the group later (obviously, this works in towns and cities, but not when you're moving by bus from Point A to Point B).

And there still are some places (Italy, France, and, indeed, most of western Europe) where the sheer density of interesting things to see is such that I wouldn't want to be limited to a group's itinerary. There, renting a car can definitely be the way to go.

One tool that you may find useful regarding weather, is a web-site called “timeanddate.com" The site provides day-by weather information — temperature, humidity, precipitation, plus additional stuff you may not need, like wind direction. You can get either averages, or perhaps more usefully, actual observations over the past several years.

One hint: always check to see which weather station was used for the data you're looking at. This may not matter much for a small country like Costa Rica, but for remote places in a larger country, it may.

Thanks! A very useful site to know about!

Aurelian, we did a Road Scholar tour at the beginning of January this year and had a terrific time. We were on the "Best of Costa Rica: Exploring Natural Wonders" trip and weren't bothered by crowds at all, perhaps due to the nature of the trip. The only place that was rather crowded was the second to last stop along the Central Coast: Hotel Punta Leona. That hotel is a large resort but it did have a lovely beach and a good restaurant.

We were very lucky with the weather as it rained during the night quite heavily a couple of times but we we only had brief light rain once during the day. The temperature varied from pleasant to warm.

Our tour guide was excellent and we were with a very nice group of like-minded travelers. I am happy to answer any questions you may have about our trip.

I don't think you should worry about crowds in Costa Rica. I have been there in February, March, April and May. Weather was fine every time I visited. Most recently I was there at the beginning of this month (March) and crowds were not a problem. Though I travelled in different places than your itinerary includes. Weather is the most important factor, in my opinion. So I would choose "high" season.