I do an awning style window that opens out, with hardware cloth attached to the framing, and sandwiched between 1 x 3's. That allows the windows to be open even when it's raining, and the hdw cloth keeps the critters out.
@lazy gardener I'm getting ready to do my windows, and what you have sounds a lot like what I was thinking based on a video that I saw and some reading. Do you by chance have a picture of one of your windows?