The critical thermal maximum (CTMax) of Peucetia viridans Hentz 1832 adult spiders was determined in the laboratory. Mean temperature at death was higher for gravid spiders (49.4° C) than for postparturient females (47.2° C) and males (46.9° C). Painted copper spider models placed in the environment to examine available temperatures predicted that spider body temperatures would rarely exceed 40° C thus making it unlikely for P. viridans to naturally reach CTMax, at least in the climate of central Tennessee.