The Brief The Phoenix Zoo has implemented adjusted summer hours, opening early and closing at 1 p.m., to protect both visitors and animals from intense heat. When it comes to the summer heat, the Phoenix Zoo takes things seriously. "We're open at 6 a.m. for members, 7 a.m. to the general public, and we close at 1:00, because anything after one is just too hot for anybody," Phoenix Zoo Vice President of Marketing Linda Hardwick said. And then the last guy leaves at about 1:00 in the morning," Davis said. "I hum Christmas music when we're putting up our lights," Davis said.