Logistics
What to lock down before you go
Mid-September is still part of Hawaii's drier summer pattern. Kauai's North Shore is naturally greener and can see passing showers at any time, but it is not yet in its heavy winter surf/rain pattern. Expect warm days, intermittent trade-wind showers, and better swimming odds on north-shore beaches than in winter, with the South Shore still holding the edge for all-day sun consistency.
If Hā'ena State Park, Ke'e Beach, or the Kalalau Trail day hike are on the list, reservations should be treated as essential planning items rather than optional extras.
With the first 3 nights at Hanalei Colony Resort, the
main logistics question is no longer whether Hanalei town is walkable.
It is whether you plan your west-side beach, park, and dinner drives
intentionally enough to avoid unnecessary backtracking.