Urban climates differ from those around them in one key way; they are usually warmer by a degree or two. This affect is known as the 'urban heat island' and it is a product of the heat that is generated by all of the buildings and of their ability to absorb solar energy and give it off again as detectable heat. It results in a local habitat where it is possible to grow plants that might not survive outside the city. This means that you can grow Carolinian species that are found only in small sheltered pockets in the Carolinian zone. In the Hamilton area this increase in temperature adds to the moderating effect of nearby Lake Ontario so that the Hamilton climate is usually very mild.

The soils found in urban habitats often differ from the soil before the area was developed. When houses are built, soil is removed to make basements and foundations. The soil that is replaced around the house after it is built may not be the same soil,it may be from a different area entirely. If it is the original soil, it may be dumped in upside down so that the surface soil is not like it was originally. Soil used in housing developments is often called 'fill' because whatever is available to fill in the hole is used. People often find garbage in their soil, and rocks that don't seem to belong.