I had a Metzeler rear tire that wouldn't seat on the bead, I removed the valve core on the valve stem, loosened the tire on the bead, lubed the bead area on both sides with liquid dish washing detergent, inflated the tire to 100 psi, and it seated with no problems .
Setting it out in the sun wouldn't hurt at all, if it's sunny there .
It's 114 F. (46 C.) out on the back patio at 1600, that would get the tire softened up a bit !!!!!!!!! .