Microclimate

A microclimate is a small area whose temperature differs from its surroundings — a south-facing wall that behaves a half-zone warmer, a frost pocket at the bottom of a slope that behaves colder. Zone maps smooth all of this away; a city garden can realistically plant a week or two earlier than the map's median. Our zone medians span real ranges — see the typical-range columns on any zone page.

See also: Plant hardiness zone