We measured temperature variation in a free-ranging ectotherm by attaching micro-dataloggers to the carapaces of 34 painted turtles (Chrysemys picta) in a farm pond located in Davidson, NC. Water and mud temperatures (T_w) were simultaneously monitored. We successfully recorded external shell temperature (T_s) in 18 turtles from September 2001–April 2002 and 23 turtles from April 2002–October 2002. Turtle temperatures steadily decreased through the fall and basking continued until the middle of December. Minimum yearly T_s (1–3 C) occurred during the same week (2–7 January 2002) for all turtles. Turtle temperatures then steadily rose and basking resumed in February. More basking events took place during February and March than during other months of the year when C. picta used basking to reach T_s 5–16 C above the maximum water temperature. During the summer, turtle T_s reached values similar to those achieved via basking during cooler months, apparently without leaving the water. The number of basking events per month was significantly different between consecutive months for seven of eleven consecutive month pairs. Contrary to our predictions, more basking events were recorded for male turtles than for females overall for the year. Monthly basking profiles were also significantly different for male and female turtles, with males basking earlier in spring than females. Mean maximum weekly T_s were significantly higher for males than for females. Our research documents seasonal variation in temperature and basking behavior in C. picta, as well as the importance of basking for achieving high temperatures during cooler months. We demonstrate the effectiveness of microdatalogger technology for measuring temperature variation in small reptiles and we contribute to a more complete understanding of the thermal biology of C. picta.