A microclimate is a small but distinctly different climate within a larger area. For example, in a garden, a spot that is sunny and protected from the wind 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 they can also get much larger; valleys and hills classically have their own climates, due to a variety of factors that 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 this type of area can be very important. For example, an architect who thinks about the specific climate at a home site can set up a house that 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 such areas to grow plants that are not supposed to grow in the regions they live, and to landscape in a way that 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 environments to thrive in, sometimes causing a double-take as people identify ones that are not normally present in a particular area.
The conditions in such locations are affected 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, 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 an area, especially for people who are new to the region. Usually, at least a year or two will be needed to identify an area of a garden or neighborhood as having a distinct climate, although people can sometimes get help from neighbors. It is not uncommon for different sides of a street to have markedly different ones, for example, or for some neighborhoods to be warmer or cooler than others.