The answer to 'when to aeration' is that the best time to aerate your lawn is in the fall, typically between September and November. Aerating your lawn helps relieve soil compaction, improve water and nutrient absorption, and encourage healthy root growth. This is an important maintenance task that should be done annually or every 2-3 years, depending on the condition of your lawn.
Aerating in the fall allows your lawn to recover and thrive before the winter dormancy period. The cooler temperatures and increased rainfall in the fall also create ideal conditions for the grass to recover and fill in any bare spots after the aeration process.