The reproductive performance of a large Great Blue Heron (Ardea herodias) colony was documented and the potential effects of weather on reproductive performance was investigated. Annual surveys were conducted during the last week of May or the first week of June between 1992 and 2004 and were designed to count all fledglings and nests in and around the heronry. Mean number of fledglings per nesting attempt during the 13-year interval was 1.57 ± 0.22 fledglings (range: 1.14 to 1.87). Mean number of fledglings per successful nest during the study was 1.80 ± 0.18 fledglings (range: 1.44 to 2.06). The number of fledglings per nesting attempt was similar to other long-term studies for the species, but the productivity based on fledglings per successful nest was typically lower. Stepwise regression analysis indicated that both fledglings per nesting attempt (active nest) and fledglings per successful nest were significantly influenced by weather patterns (number of days with greater than 0.30 inches of rain and average monthly wind speed) during the month of May prior to fledgling.