Hot car with newborn in it, need advice

So im due in January and I live in Southern California, even though its winter technically we still can reach about the 90s and then by March were back to the 100s. My question is I have a compact SUV so there are only AC vents in the front, not the back and the ac doesn't reach all the way back there until like 30 mins after I've been running it. Its way too hot to have my baby back there not getting direct AC. Do any of you have this problem? Any recommendations on how I can help this without having to run my car for 20+ minutes before putting baby in?

Any advice is appreciated, thank you!