One could argue October to be the most critical month for lawn maintenance. Work you put in now may not show immediate results, but that work will create a healthier lawn in the spring and summer to come.
This is the time of year summer weeds begin to finish up for the season. Simultaneously, winter weeds are beginning to emerge.
This is a two-fold problem. Summer weeds create a supply of seed for next season and domant seeds will do their work in spring and summer. Meanwhile, winter weeds are beginning to emerge.
Thankfully, combating these issues is a fairly simple task.
Consider a preemergent herbicide on your lawn this season to prevent winter weeds from emerging.