Winter gets all the checklist attention, but summer heat causes its own slow damage — cracked dashboards, degraded electronics, faded upholstery. None of it happens in one day, which is exactly why it's easy to ignore until it's done.
Windshield sunshade, every time
A reflective foldable sunshade is the single highest-leverage item here — dashboard surface temperatures can climb dramatically in direct sun, and a shade meaningfully cuts that down just by blocking direct light through the glass.
Crack a window slightly if parked long-term
A small gap helps hot air escape rather than building up, though this is a tradeoff against security and rain exposure — reasonable for a driveway, less so for a public lot.
Electronics don't like heat either
Dash cams, phone mounts, and anything left plugged in are all rated for a maximum operating temperature — a closed car in direct sun regularly exceeds it. Where possible, unplug or remove electronics you're not actively using rather than leaving them baking on the dash.
Check tire pressure more often
Air expands with heat, so tires run higher pressure in summer than the same tires would in winter. Check monthly rather than assuming the reading from a cooler month still holds.
Leather and vinyl protectant
A UV-protectant interior cleaner applied every few weeks in peak summer slows the fading and cracking that direct sun causes over a season — cheaper than reupholstering later.
If you only do one thing from this list, make it the sunshade — it's the cheapest item here and addresses the root cause (direct sun on the dash) rather than working around the damage afterward.