Kona sää — huhtikuu

Hawaii Volcanoes-forum threads on early April weather are direct that this sits among the wetter, cooler months at the park, real rain expected across much of the month and posters describing days that can feel genuinely chilly when wind accompanies the wet weather, a sharp contrast to the sunny coastal image most visitors expect from Hawaii. Lower-elevation sections of the park can still see real temperature swings and sunnier stretches even on an otherwise damp day, so conditions vary meaningfully by exactly where in the park a visitor is standing. Layered, water-resistant clothing is standing advice rather than optional. Posters are consistent the park stays genuinely worthwhile despite the rain, several reporting they simply timed sightseeing between passing showers rather than letting the forecast cancel plans outright. The record: 18.8C days feeling like 19C, 13.8C nights, an extraordinarily high 282mm across nearly 23 days, an 25C sea and 83 percent humidity.

Kona forum regulars are consistent about September: it's hot and sticky, and the trade winds that usually cool the coast can break down for stretches, so there's less relief than you'd expect. It's still technically hurricane season, and while a direct hit is rare, the remnants of a passing system can bring heavy surf and a burst of heavy rain even on an otherwise sunny week. That said, several posters described near-perfect two-week stretches with no crowds and easy access to snorkeling spots - it's a gamble, but one that tends to pay off more often than not.

March in Kona is the tail of whale season — humpbacks run from about mid-December to late March, thinning as the month goes on, so mid-March is still reliable and the very end of it is not. On rain, the forum's line that March is one of the Big Island's wettest months is about the windward side: on Kona's leeward coast March is one of the drier months, ten rain-days against fourteen through the summer. The variable that is genuinely local is vog — volcanic haze concentrates in the Kailua-Kona area and can bring headaches and eye and lung irritation, more seriously for asthma. The regulars' fix is geographic: drive north a few beaches and it largely clears.