The best time to go is when Kilauea is really pumping. If you're lucky, you'll be in the park when the volcano is really active and fountaining; mostly, the lava runs like a red river downslope into the sea. If you're on another island and hear a TV news bulletin that the volcano is acting up, catch the next flight to Hilo to see the spectacle. You won't be sorry--and your favorite beach will still be there when you get back.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.