This indicator measures trends in the length of the growing season at Basin Boundary weather stations. Only stations with at least 100 years of climate data are referenced. The growing season is defined as the annual number of days between the first annual span of at least six days with a daily mean temperature of greater than 5 degrees Celsius, and the first span after July 1st of 6 days with a daily mean temperature of less than 5 degrees Celsius. Index values were acquired from the CLIMDEX data portal. Trend analysis was completed by the RDI research team using ProUCL software, a statistical package developed by the US Environmental Protection Agency.