Yeah, but only if the temperature stays REALLY warm all day and all night.
Garages get hot because the sun beats down on them during the daytime. If the temperature cools down at night at all, the inside of the coolers doesn't get very warm.
My part of Montana isn't the coolest in summer, but nights still cool down to around 70 at most during July and August. I've tested my coolers with a thermometer placed inside, and the temperature never rises much above 70 even during the hottest days. Of course, I have the coolers on the floor and in the shade, not in front of a window where the sun will hit 'em.
