Biosphere 2 Is Tucson's Closest Climate-Controlled Day Trip: Inside the 3.14-Acre Glass Research Campus 30 Miles North of the City in Oracle Where University of Arizona Scientists Run a Rainforest, a Coral-Reef Ocean, and Five Other Biomes Under Glass — Open Daily With Summer Tour Hours 8 a.m. to 2 p.m., $29 Adult Admission, and the Self-Guided Walk-Through That Most Tucson Locals Still Haven't Done

Biosphere 2 — the 3.14-acre, glass-enclosed earth-science research campus in Oracle, Arizona, owned by the University of Arizona — is one of the closest indoor-and-climate-controlled day trips for Tucson households as June 2026 heat sets in. Per Biosphere 2's own visitor pages and Visit Tucson's listing, the campus is at 32540 South Biosphere Road, Oracle, AZ 85623, roughly a 45-to-50-minute drive north of central Tucson via Oracle Road and Arizona State Route 77, just past SaddleBrooke Ranch at Mile Post 96.5. Per the University of Arizona, the structure was built between 1987 and 1991 as the largest materially closed ecological system ever constructed, ran two sealed human missions in 1991-1993 and 1994, transferred to Columbia University management in 1995, and was acquired by the University of Arizona in 2007 with full ownership in 2011. Per NPR's July 2025 feature and Scientific American, the site is now the world's largest controlled environment dedicated to climate research, with active coral-reef-resilience experiments in the ocean biome and the Landscape Evolution Observatory hillslope project under one roof. Per Biosphere 2's published admission and hours, general admission is $29 adult, $27 senior, $15 youth 5-17, free under 5; the campus is open 9 a.m. to 4 p.m. daily except Thanksgiving and Christmas, with summer tour hours typically 8 a.m. to 2 p.m. for last entry. Here is the May 28, 2026 sourced Hidden Gems walk-through for Tucson residents, Oro Valley, Marana, SaddleBrooke, and Catalina neighbors, and relocation buyers weighing the cool-indoor side of southern Arizona's summer calendar.