With regards to wildlife watching, October can be quite a tough month. Increased rainfall leads to muddy terrain, which is sometimes impassable due to landslides or high river crossings. Walking through the national parks themselves, especially on the Pacific Coast, can be hard work, and seeing wildlife is not as likely as, similar to us, they prefer to shelter from the rain, and are often hiding away.
Over on the Caribbean coast, it is still green turtle nesting season, and you may be able to see the eggs hatching, or the tiny hatchlings making their way to the sea for the first time - a wonderful experience for anyone who loves wildlife and nature. This season lasts from July to October, so you can go earlier in the year if you want to avoid the heavier rains of October. Average rainfall in Tortuguero National Park at this time is 330mm, whilst the temperature still averages at 30 degrees Celsius.
If you are planning to explore San Jose and the Central Valley, the rainfall is high here too, at an average of 326mm for the month. The Central Valley is stunning at this time, and the rains of the previous few months have worked their magic and encouraged a huge amount of growth. This is relevant throughout most of the country which is vibrant and green in October - a pleasure to photograph.
It is still humpback whale season in Dominica, and you can spot them before they head off again away from the coast gathered at Marino Ballena National Park.