Last year I came within days of getting the pre-emergence down too late. It would have been worthless! Spring was a couple of weeks early last year in SW Ohio.
Luckily I'd checked soil temps on this website.
It has a chart that tell you when crabgrass is going to germinate and the best time to apply pre-emergence. NO MORE GUESSING OR MISSED DATES!
It saved me. For you folks not in Michigan, Ohio or Indiana maybe you have something similar.