Pack or skip
Beanie for Hilo in May
Verdict
Skip it
Lows near 64°F — no scenario where you'll want one.
Why
Hilo in May averages highs of 81°F, lows of 64°F, 14 rainy days.
That climate means a beanie isn't pulling its weight. Lows near 64°F — no scenario where you'll want one.