Spend or save money: If money is not an issue for you, you should probably skip past this section. If stretching your money is an important goal, read on. The most expensive time to visit Costa Rica is during peak holiday seasons such as Christmas and New Years or Easter. High season dates usually consist of the months of December through April (excluding Christmas and Easter) and are the regular season rates. These rates can also apply to the months of July and August, especially in more popular destinations. The months of May and June and September through November are the cheapest months to visit as most of the country is in the middle of the rain season.
Where to visit: Costa Rica has many unique climate zones which factor into weather patterns. Planning according to these patterns can result in a successful vacation. The best weather in the Northern zone is during the months of December through August. Keep in mind that September is usually the best month for volcano observation despite the rains. Northwest Guanacaste is the driest region of Costa Rica and is generally nice from November through August. The Central Pacific is more susceptible to the rain season. The nicest weather here is from December through August. The South Pacific had more defined seasons and can see heavy rains from May through November, with the worst in August through October. The Caribbean side has a totally different weather pattern and the nicest months are September and October with good months also in February, March and August. The Central Region has a fairly defined green season from May through November, with the worst coming in September and October.
What you would like to do: Planning your destinations and activities based on the weather is entirely possible if you are conscious about your decisions. Most visitors would like to visit a beach destination during their trip. Planning around beach weather is a great way to start as the Pacific side can be rainy during September and October, whereas the weather is at its best on the Caribbean during this time period. With that in mind, now factor in the rest of your vacation logistically based on your desired activities. For example; if you would like to do adventure activities and see a volcano during the months of September and October, it would be recommended to visit the Turrialba Volcano area and then a Caribbean beach area. If you would like to see wildlife during the same time period, first go to Tortuguero and then a beach area further down the coast. On the other hand, if you are looking for volcano and adventure and a beach area any other time of the year, you are probably going to want to go to the Arenal Volcano area and a Pacific beach destination.
Here are links to pages that describe what to expect each month: