A microclimate is the climate of a small, specific place within an area as contrasted with the climate of the entire area, or the "macroclimate." The climate of the entire area is indicated by where a region lies in the USDA Plant Hardiness Zone (simply "zone" for short).
How Microclimates Aid You in Landscaping
Now that I've answered the question, "What are microclimates?" let's consider why it's important to learn about them.
Beginning gardeners and landscapers should plant according to the standard growing zones as indicated by the regional maps that the USDA furnishes for gardeners. But growing plants not suited to your region's climate is sometimes possible, if one knows how to exploit microclimates. That's why this is not just an academic issue, but rather helpful information to know.
For instance, sunny nooks in your yard that are sheltered from harsh winds and frosts contain microclimates. Such microclimates are excellent for experimenting with plants otherwise considered too tender for your region. Let's say you're in zone 5, and the plant you'd like to grow is supposedly hardy only to zone 6. Try growing it in the microclimate of a sunny, sheltered nook. Success isn't guaranteed, but you will have increased the likelihood of the plant's survival considerably.