Just a guess, but seeing the two individuals in the background to give the stands some scale, I'd say probably the Giants' spring home in Phoenix in early 1964? Here's a link to a pic of Mays in what is claimed to be Casa Grande in 1962, but all other information I can find places them in at Phoenix in all the springs from the 1950s to the 1970s. There are several errors in this photo retrospective so it is possible this is Phoenix. And at first blush the stands look like they could be a match - light colored.
And he's wearing his away jersey at their "home"....
https://projects.sfchronicle.com/202...ring-training/