Acorn squash is available in some areas in summer months, because it is harvested from summer into the winter. However, it is considered a winter squash because it stores well through the winter and is traditionally found in stores beginning in the fall.
Acorn squash seeds are planted after the threat of the last frost in the spring. They generally take about 80 to 100 days to grow before they are ready to harvest. Some gardeners plant acorn squash throughout the summer season, depending on the region and temperatures. Acorn squash stores well outside the refrigerator until it is cut or cooked.