A microclimate is a small but distinctly different climate within a larger area. For example, if you have a garden, a spot which is sunny and protected from the wind could be considered a microclimate, as it will be significantly warmer than the rest of the garden for most of the year. In this case, the microclimate would be extremely small, but microclimates can also get much larger; valleys and hills are classically microclimates, due to a variety of factors which cause their weather to be different from the more general weather in the region.

Microclimates are often a topic of interest for gardeners and architects, because learning to work with a microclimate can be very important. For example, an architect who thinks about the microclimate at a home site can set up a home which will be more energy efficient, by taking advantage of the natural features to keep the home cool in the summer and warm in the winter, rather than building a house which will fight with the land. Gardeners can use microclimates to grow plants which are not supposed to grow in the regions they live, and to landscape in a way which will make an efficient use of water.

Biologists often have an interest in microclimates as well, because they can sometimes sustain unique or unusual species in an area where these species are not normally found. Unusual plants often find microclimates to thrive in, sometimes causing a double-take as people identify plants which should not be present in a particular area.

The conditions in a microclimate are impacted by a number of factors. The slope of the land can be important, as is the direction in which the slope faces. The amount of shade, wind, exposure, and drainage will also all impact the conditions in a microclimate, as can things like a nearby body of water or the presence of an urban area. Urban areas are notorious for being much warmer than the surrounding open land, because the buildings, sidewalks, and pavements reflect heat.

It can take some time to recognize microclimates in your area, especially if you are new to the region. Usually at least a year or two will be needed to identify an area of your garden or neighborhood as a distinct microclimate, although you can sometimes get help from neighbors. It is not uncommon for different sides of a street to have markedly different microclimates, for example, or for some neighborhoods to be warmer or cooler than others.