August: Warm water, calm lakes and the Perseid meteor shower (mid-August) in a certified dark-sky park. It's the best month to paddle and camp on the islands.
Permits and reservations
No entry reservation. Tent campsites, houseboats and boat tours are the things that need booking.
Campsites & houseboat sites: Every tent campsite needs a reservation (reservation fee plus nightly fee). Peak-season reservations open the previous November 15 at 9 a.m. Central, and off-season sites are $10 a night.
Boat tours: Tour tickets go on sale at 9 a.m. on April 15 each year (Recreation.gov or 1-877-444-6777) and usually fill.