Microclimates can be found in even the samllest of yards. In fact, it's hard to find a piece of property without one. A hedge, a house, or even someting as simple as a stone wall can alter its immediate setting enough to create a microclimate. Trees and shrubs with tender flowers or buds face a tough fate in warm microclimates. Early spring warmth may trick them into flowering too soon, only to ruin the display with a late frost.
Hillsides can create a microclimate too.
A garden on a south-facing side of a slope warms up sooner in spring and cools down later in fall than one on the north side. Even on the same southerly slope, frost hits the garden at the bottom later in spring and earlier in fall. That's because cold air flows downhill. Keep an open mind and open eye to all areas in your own garden to determine where your microclimates are located. It's an subject that can ultimately effect the tree, shrubs and plants in your garden.