When should I aerate my lawn?

The consensus is that you should aerate your lawn at least once a year.

This does of course depend on your lawn and where you are, but the best times of year would be, normally, during spring or autumn. It is easier in the growing season because the grass is active and will recover faster from any damage and grow to cover any scarring or holes (if you use a hollow tine).

If you are to do it only once, we would suggest the spring period is the most essential. 

N.B. Weather and ground conditions will, of course, make a difference. if the ground is very hard, after a long dry spell or when frozen,  it will be extremely difficult to penetrate the soil and if it is too wet, the machine will cause more mud, which may well become even more compacted and may harm the grass.