Although Costa Rica lies between 8° and 11° north of the equator, local micro-climates predominate and make temperatures and weather unpredictable, though to an extent you can depend upon the two-season rule. From roughly May to mid-November you will have afternoon rains and sunny mornings. The rains are heaviest in September and October and while they can be fierce, will only impede you from travelling in the more remote areas of the country - the Nicoya Peninsula especially - where dirt roads become impassable to all but the sturdiest 4WDs. In the dry season most areas are just that: dry all day, with occasional blustery northern winds blowing in during January or February and cooling things off. Otherwise you can depend upon sunshine and warm temperatures.

In recent years Costa Rica has been booked solid during the peak season - the North American winter months - when bargains are few and far between. The crowds peter out after Easter, but return again to an extent in June and July. During peak times you have to plan well in advance, faxing the hotels of your choice, usually pre-paying or at least putting down a deposit by credit card, and arriving armed with faxed confirmations and a set itinerary. Travellers who prefer to play it by ear are much better off coming during the rainy or low season (euphemistically called the "green season"), when many hotels offer discounts. The months of November, April (after Easter) and May are the best times to visit, when the rains have either just started or just died off, and the country is refreshed, green, and relatively untouristed.