The National Park Service is offering three fee-free weekends this summer at national parks across the country. The first weekend is Father’s Day Weekend, June 20-21. The other weekends are July 18-19 and August 15-16. Denali National Park and Preserve is the only National Park System unit in Alaska that charges an entrance fee. The fee free weekends will apply there, but with some conditions. Visitors who have made advance reservations for park campgrounds, shuttle bus seats, or a bus tour have already paid an entrance fee and will not receive a refund. The no-refund policy is being applied across the country. Visitors who arrive at Denali without an advance reservation will have the entrance fee waived when they obtain their campsite or bus ticket on any of the six fee-free days. The normal entrance fee at Denali is $10 per person or $20 per vehicle.