On another forum, several have us have been doing some experiments involving cars in hot sun - inside temp vs. outside temp, ttrunk temp vs. inside temp, etc. I decided to take a different approach.
At 10:00, I parked my car in a parking lot that should receive full sun all day. The car doesn't have a trunk, so the case is sitting in the back seat. Here's the car:
I cracked the windows and the sunroof. Weather.com said it was 84 degrees out. Here's what the thermometer in the case says:
The thermometer is an ancient one that was mounted on the house sometime around 20+ years ago. Here's what I did with the case:
Yeah, that's some scarves and some microfiber cloths. And a shirt. They happened to be in the car; and that's what I would use in a real-world application.
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Here's how things looked at lunch. Weather.com said it was 88.
The sandwich was roast beef with peppers on marble rye.
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I wasn't able to get back to the car until 6:40. Here's what I found when I opened the case:
I guess that would be somewhere around 113 degrees. That's after 8 hours and 40 minutes inside a case, inside a car that has a whole lot of glass to let light in - the roof itself is 60% tinted sunroof. Of course, I left the windows and sunroof cracked.
Outside temp when I took the photo was right around 92.
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So what does all this mean? I don't think it means that we can leave cars in the sun all day and expect nothing to happen to a guitar inside.
But, I personally am not going to be too worried if I leave the guitar in the car while I run some errands.