`Atlantic' potatoes (Solanum tuberosum L.) are grown on approximately 8100 hectares with seepage irrigation in Northeast Florida's Tri-County Agricultural Area (St. Johns, Putnam, and Flagler counties). `Atlantic' is preferred for its chipping quality, high specific gravity and yield, but is susceptible to internal heat necrosis (IHN), a physiologic disorder that affects potato tuber quality. The relationships of environmental stressors (growing degree days, GDD and rainfall) to IHN were evaluated on two fields (fields 3 and 4) on a local producer's farm. IHN reduced marketable tuber yield by 100% in the 1995 and 2003 seasons, but not in 2001 and 2002 seasons. From 3 to 6 weeks after planting (WAP), GDD for 1995, 2001, 2002, and 2003 were 470, 325, 386, and 628 (45° F base), respectively. This is the only 4 week period during the 14 week season that GDD accumulation by week was different among treatments. Average rainfalls (cm) for the same periods were 1.60, 1.12, 2.23 and 7.91, respectively. Both warmer/dryer and warmer/wetter early season conditions occurred during seasons with higher rates of IHN. Although circumstantial, higher accumulated heat units and water stress within the first 6 weeks of the growing season resulted in higher percentages of tubers with IHN. These relationships should be evaluated further with other growers.