So, is Hawaii Weather perfect even in January and February? Well, yes and no. In all of Hawaii, January and February are some of the coolest months, and February is sometimes the beginning of an incredible rains (which always make it cooler).
HOWEVER, every single major island in Hawaii has a dry side and a wet side. It almost never rains on the entire island at the same time. Chances are, if it’s raining where you are, it’s dry and sunny on the west side (the dry side).
Also, the ocean is still warm – 75 degrees or so, and the general temperature is still warm. Usually anywhere from 75 to 85 and it can even get warmer in places like Kona and Waianae and Ewa.
So, you’ll still be able to swim. You’ll still be comfortable and warm. The sun will still fry you. Actually, January and February may be more comfortable months for weather than summer because in summer it is downright hot and if I’m not in the water, I don’t tend to have any energy for sightseeing or hiking or anything.
You might want to avoid Hilo in January and February, but other than that, you’ll have a great time. Have fun!