It's hard to tell what the cause of the spotting is for certain. Several leaf infections on squash can cause similar symptoms that are difficult to differentiate, and even abiotic stress (that caused by growing conditions and not a pest or disease) can mimic symptoms of a disease. Our primary guess based on the pictured symptoms is Angular Leaf Spot, a bacterial infection, though we usually don't see it very early in the season due to the pathogen's preference for warm conditions. (Granted, we have had a few warm spells so far, and if that is the disease present here, it is in the earlier stages before dying leaf tissue creates holes in the center of affected spots.) It's not a perfect match for symptoms, since a few of the spots don't seem to be confined in shape by leaf veins, a trait characteristic of Angular Leaf Spot.

Was anything sprayed on or near the plant in recent days/weeks, like a fungicide or insecticide?

For now, monitor the plant for worsening or changing symptoms and feel free to send us more photos if that happens. To reduce the risk of disease overall, make sure the planting continues to receive good air circulation, and that its foliage is kept as dry as possible once regular watering is again needed. (If wetting the leaves is unavoidable when irrigating, water early enough in the day so that the foliage can dry by nightfall. Wet leaf surfaces are easier for pathogen spores to infect.) While a few fungicide products can suppress some of the common vegetable leaf diseases, they aren't always completely effective, usually require multiple repeat applications, and might risk harm to pollinators that need to visit the squash blossoms. Plus, as to the reason we asked about nearby sprays, sometimes a pesticide can cause phytotoxicity (plant tissue damage from chemical exposure) if conditions of weather or plant stress make it vulnerable to injury.

Miri