The microclimate of a particular area is determined by the unique factors that change the way precipitation falls, or how temperature changes in a space. Maybe there’s brick wall that gets a lot of sun in your garden and it keeps things near it above freezing during the wintertime. Maybe the way your gutters line up leads to a consistent wet spot in the yard no matter how little it rains. Microclimates are best known by observing the area you are working in, and noticing all its quirks. Some things to look for when observing:
Look at how the sun moves across the space. Similar to the Windowsill environment, the direction your outdoor space gets the most sun from matters. Yards that are open towards the south with get more light and will likely be slightly warmer than yards open to the north, east, or west. When watching look at what parts of the yard get continual sun, and what portions only get sun for a few hours a day at most. Additionally, structures like buildings, walls, and roads all absorb a large amount of heat during the day, and radiate it out at night. If you are in a concrete jungle, your microclimate will often be warmer than your macroclimate zone.
Another thing to look for on the ground are areas where water tends to pool and puddle. Not many garden vegetables will tolerate these soggy conditions, however there are many other lovely plants that will, like willow!