I just see how much light it gets at certain times of day. Morning, afternoon and late afternoon. If it gets sun all throughout the day, then it's full sun. If it only gets sun per part of the day, then it's part sun/part shade. If it doesn't get sun at all, it's shade.

When trying to landscape the design of your home, you always want to keep in mind the amount of sun that each plant needs. It is good to understand what full sun, partial sun/partial shade and Full shade really mean.

Full sun means that the area gets at least 6 or 7 hours of direct sunlight during a complete day. Typically plants in this area need lots of water.

Partial Sun or Partial Shade typically means that this area gets anywhere from 3-5 hours of sun light, normally in the morning or afternoon.

And lastly Full Shade means that the area gets less than 3 hours each day. Full shade does not mean that the area is getting no sun at all. In fact this typically means that the area is getting filtered sun throughout the day.

Hope this helped!

Here is a link that might be useful: Landscape Design Barrie

When you're home all day one day, look at your yard once every hour and make notes. By the end of the day, you'll have a total for each area of how many hours of sunlight is received. I don't count early morning or late evening light that is not strong enough to cast shadows.