I have seen dash boards melt, but that was overseas.

If JI needs to stash a vehicle with kits inside, she will need to choose the parking area to ensure that it does not get direct sunlight for too much of the day. A parking area in the shade, with good packaging of the kits should prolong the life for months rather than days. Multiple layers of insulation may help, with the fluctuations of temperature over a 24 hour period. Understanding material and packaging is important for this.