April: Spring is the best time for the Needles district's long loops, with cool mornings, warm afternoons and slickrock that won't cook you.
October: Crisp fall weather returns the Needles and Island in the Sky to prime hiking condition, and October skies are clear and dark.
Permits and reservations
Timed-entry reservations are not required.
Day-use permits (4WD roads, bikes): Required for every vehicle, motorcycle and bicycle on White Rim, Elephant Hill, Lavender Canyon and Peekaboo/Horse Canyon roads. Not needed on Potash Road or Shafer Trail. Reserve online on Recreation.gov starting 8 a.m.
Overnight backcountry & river permits: All backcountry camping requires a permit. Reservations open about 4 months before each season at 8 a.m. MT and close 2 days before your trip.