There's no time slot that guarantees less mist at Cave of the Winds.

No. The mist depends on wind direction and water flow, not the time of day.

Cave of the Winds gets you right under the Bridal Veil Falls. If the wind blows the mist toward you, you’re soaked regardless of whether you go at 9 a.m. or 3 p.m. The only predictable variable is seasonal: spring and early summer have higher water flow (more mist). Late summer and fall are slightly better for staying drier, but “better” is relative—you’re still getting wet.

They give you a poncho and sandals for a reason. Embrace the wet. If you really want to minimize it, go on a calm, windless day if you can check the forecast. But that’s not a time slot—it’s a weather guess.

Assume you’ll get soaked and plan accordingly.