A small area with climate conditions (temperature, humidity, wind, light) differing from the surrounding region due to local features like buildings, slopes, or water.
Your backyard has multiple microclimates. A south-facing wall is warmer and drier than a north-facing slope. A low spot collects cold air and frost. Near a building, heat radiates making it warmer. Understanding microclimates lets you grow plants outside their typical hardiness zone in favorable spots or protect sensitive plants in harsh microclimates.
Microclimates explain why one part of your garden thrives while another struggles. Using microclimates strategically lets you stretch your growing season and grow marginal plants.