Escaping prey decide whether to enter and how long to stay in refuges. According to refuge-use theory, hiding time increases as costs of emerging increase and costs of staying in refuge decrease. We studied effects of air temperature on probability of entering refuges and the effects of thermal cost on hiding time (duration in refuge). Few striped plateau lizards (Sceloporus virgatus) used refuges at intermediate air temperatures, but most readily entered cool refuges at the lowest air temperatures and relatively warm refuges at higher temperatures. Because running speed in lizards decreases as body temperature decreases, S. virgatus that are cool upon morning emergence presumably reduced their probability of being captured by entering refuges. As air and presumably body temperatures increase, refuges are initially cooler than outside, contributing to infrequent use. At higher, but not thermally stressful, temperatures, a greater probability of using refuges may reflect lower thermal costs in refuges that have warmed. Hiding time decreased as temperatures became cooler in refuges than outside. Our results confirm previous work on actively foraging lacertid lizards showing that hiding time decreases as thermal costs of refuge use increases, and extend this finding to a very distantly related phrynosomatid species that is an ambush forager. Thus, the thermal cost of refuge use affects hiding time even in lizards that do not require high body temperature for prolonged foraging movements. A growing body of knowledge supports the hypothesis that tradeoffs between costs of emerging and remaining in refuges guide decisions about hiding time.