Would like to see when others in the Midwest, specifically MN & WI, are planning to put down Crabgrass pre emergent?

It has been a colder than normal spring but it looks to be warming up significantly in the next week. I know that crabgrass begin to germinate when soil reaches 50 degrees for a few consecutive days. Local extension office has soil temps at 35 degrees as of 4/21/13.

Thanks