Growing degree days (GDD) quantify the heat accumulation that plants and insects experience over the growing season. Heat accumulation drives plant and insect growth, crop development, and the timing of other physiological processes such as flowering. Here they are presented at the seasonal (winter, spring, summer, fall) scale. The GDD for a single day are calculated as the mean daily temperature minus 50°F. So, a daily mean temperature of 65°F yields 15 GDD. 50°F is a commonly used as a basis for the GDD calculation as it represents the minimum temperature threshold for growth in multiple crops (e.g. corn and soybeans). In this tool, the GDD for each day is totaled across a season, and negative GDD values are not incorporated because GDD are only meant to quantify the time and intensity of temperatures above 50°F that drive plant and insect growth.Climate observations and projection data provided by the Northeast Regional Climate Center at Cornell University through their Applied Climate Information System (ACIS, rcc-acis.org). The Localized Constructed Analog downscaling projections were obtained from the Scripps Institution of Oceanography (http://loca.ucsd.edu). Time periods are simulated using greenhouse gas emissions scenarios RCP 4.5 (moderate emissions) and RCP 8.5 (high emissions). The modeled data have been extracted from the U.S. National Oceanic and Atmospheric Administration's Applied Climate Information System and localized to New Jersey.The Applied Climate Information System (ACIS) was developed and is maintained by the NOAA Regional Climate Centers (RCCs). It was designed to manage the complex flow of information from climate data collectors to the end users of climate data information. The main purpose of ACIS is to alleviate the burden of climate information management for people who use climate information to make management decisions.