Coolseason

Coolseason is a term used in meteorology and horticulture to describe a period of cooler temperatures, or the set of crops and plants that perform best under such conditions. It contrasts with the warm season, and the exact timing and definitions vary by region and context. In climate discussions, cool season refers to the part of the year when temperatures are cooler relative to the warm-season months.

In temperate regions with four distinct seasons, the cool season generally includes late autumn, winter, and early spring. In the Northern Hemisphere, it typically spans roughly October through March; in the Southern Hemisphere, April through September. The exact timing depends on latitude and local climate, and some definitions use calendar months while others rely on prevailing average temperatures as the criterion.

Cool-season crops are those that thrive in mild to cool temperatures and can tolerate light frost. They tend to decline in heat and may bolt or wilt under prolonged high temperatures. Common cool-season crops include lettuce, spinach, kale, broccoli, cabbage, peas, radishes, and onions. They are often planted in early spring or late summer for fall or winter harvests, depending on the climate.

Cool-season grasses are used for lawns in temperate climates and prefer cooler temperatures. Examples include Kentucky bluegrass, perennial ryegrass, and fescues. These grasses grow actively in cooler weather and may enter dormancy or slow growth during heat, influencing irrigation and maintenance needs. In agricultural planning, cool-season concepts help organize sowing calendars, frost risk awareness, and crop rotation alongside warm-season species.