Most exterior paints sold today list a minimum application temperature somewhere around 35 to 50 degrees. Homeowners read that, look at a 52-degree October afternoon, and assume they are fine. They usually are not, and the reason is that the number on the can refers to the surface temperature during the entire curing window, not the air temperature at the moment the roller touches the siding.
A wall in Minneapolis that reads 55 degrees at two in the afternoon can be down near 35 by nine that night. Latex paint that gets cold before it has finished coalescing never forms a proper film. It may look perfect the next morning and then fail early, chalking or peeling a year or two before it should. This is the single most common reason a late-season exterior job goes wrong, and it is completely invisible on the day it happens.
Dew point matters just as much and gets ignored more. When the surface temperature falls to within about five degrees of the dew point, moisture starts condensing on the siding. Paint applied onto that film, or paint that gets condensation on it while still soft, loses its grip on the surface underneath. In practice this is why a crew should stop painting in mid-afternoon in the shoulder season rather than pushing to sundown to finish a wall.
The practical Minnesota window for most exterior work runs from around mid-May through early October, and it moves each year. Within that window, the sunny south and west walls stay workable later in the day than the shaded north side, which is why a good crew rotates around the house with the sun rather than working one elevation to completion.
If you are calling in September and someone promises to start next week regardless of the forecast, that is worth a question or two. The honest answer is sometimes that the prep gets done this fall and the finish coats wait until spring. A house that waits six months for the right conditions gets a coat that lasts. A house painted into a cold snap gets a coat that has to be redone.