Although you don't say exactly when your Spring break is, San Jose, the Pacific Coast and Monteverde should be sunny and nice as will be Arenal. You could run into serious rain in Tortugero and Puerto Viejo but it won't rain all the time and you will see sun. It will be hot and humid there.
Assuming your Spring Break is in March or early April you will not see much rain. It will be hot and dry... rains do not really start until May...
Weather is going to be warm... pack a pair of jeans in case you are going to stay in san jose....
Please....bring bug spray and just enjoy the humidity :)
I am going to costa rica for spring break this year ( San Jose, Limon, Puerto Veijo, Tortuguero, Arenal Region, Monteverde,Pacific coast... etc) Flying from Vancouver (where i live) I am used to rain and clouds and I was really hoping for some nice sunny weather. What is the weather like? Any precautions ? What should I pack?