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.
And there’s the problem. See that thing in the middle of Clark Street? That’s a Chicago streetcar. But streetcars stopped running in Chicago in June 1958. By the middle of the 1950s, as shown on this 1954 map, the Clark Street line was one of the few streetcar lines remaining.
Here are photos of other Chicago streetcars from the era. And here’s an old Chicago streetcar that looks just like the one near Wrigley in the photo above:
Also, the cars visible in the photo are all from the late 1940s and early 1950s. If this photo really does date from 1959, there might be more recent cars than that visible, although that’s certainly not a requirement for dating this one.
Going back to that license plate link, it’s possible that’s a 1954 plate. Even though that plate was white on green, the lighting or colors of the photo might have not been entirely accurate. That would match the cars better.
Also, by 1959 Wrigley had those ugly concrete panels on both the west and south sides, which have now been removed. You don’t see any of those panels in this photo. So I’d tend to lean toward a 1954 date for this photo.
Beyond the license plate mystery, there are quite a few things of interest visible in this photo. There’s a great look at the Collins & Wiese Co. coal yard that was adjacent to Wrigley until 1961, as well as the WGN-TV truck parked next to the ballpark. There are a couple of rail cars standing next to the ballpark, and you can see the railroad tracks that ran into that area until the early 1960s. Looking at this photo from Google Maps:
... you can see exactly where those train tracks would have run through Clark Street, right where the Hotel Zachary now stands. Some of the land where those tracks were, directly west of the Cubby Bear, is still vacant. Further south from there, between Cornelia and Newport, houses have been built on land where those tracks used to be.
You can also see the old terra cotta exterior on Wrigley (look between the WGN truck and the rail cars), the look the Cubs have done an excellent job of replicating in the renovation/restoration project.
The only clue as to the time of year this photo was taken is one lonely tree visible in the background (you can see it right next to the streetcar), with no leaves. With a WGN truck parked at the ballpark and lots of cars parked across the street, this almost certainly had to be taken on a game day, possibly even Opening Day. In those days WGN didn’t have multiple mobile trucks and they likely used that truck at other locations and didn’t just leave it parked at Wrigley all year.
So let’s return to that license plate. One more thing you can see on the license plate link is that back in the day when Illinois issued plates every year, the “19 ILLINOIS XX” date and the slogan “LAND OF LINCOLN” alternated on the top and bottom of the plate. This was done — and no, I am not making this up — to prevent people from simply repainting their old plate in the new plate’s colors, changing the year number, and using them for more than a year.
It’s a bit hard to read, but the plate visible in the photo appears to have “LAND OF LINCOLN” on the top and the date on the bottom, which was the case for the 1954 plate, but not in 1959. And so, I’m going to say this photo was taken in 1954. If it was 1959, that streetcar wouldn’t have been there. It’s possible it’s from Opening Day, and if so, I’d say it would have to have been during the game, otherwise more people would likely have been walking down the street.