Masovian Voivodeship in January

April through June delivers the sweet spot – dry weather, calm seas, and reasonable hotel rates. September through November offers the same perks with fewer families since school's back in session. December through March brings humpback whales but also peak prices and crowds. Summer gets hot and humid, especially on the Kona side where trade winds die down. But here's what guidebooks won't tell you: winter storms on the mainland mean cheap flights if you're flexible. I've snagged round-trip tickets from LAX for $180 in February. The weather's still better than anywhere on the mainland, even during 'rainy' season. Just pack layers – it can be 85 degrees at sea level and 50 degrees at Mauna Kea's summit.