There’s not much of Wrigley Field visible in this photo; the exterior of the ballpark takes up only about a third of the frame. And there’s no baseball action visible, so we can’t begin to sleuth out any dates from that.
Even so, I think I’ve got this one narrowed down at least to a year and month.
Your first clue is the license plate on the car visible at the right of the photo. It has a very distinctive typeface that was used on Illinois plates from around 1950 through 1978.
This site, which has a photo of every Illinois plate ever issued, at first glance appears to indicate that plate matches the 1959 Illinois plate, white on dark brown.