10w-30 or 5w-30 for high mileage 1995 V6?

From what I've read 5w-30 is better for colder climates, but is there a reason not to use it in warmer climates? I'm in Northern California so typically a warm climate, but sometimes go over the hill into the Tahoe area where it can get colder.

1995 V6 4x4

 

Whatever it says on your oil cap......

 

5w30

 

With conventional oils they had to put in more additives to make the 5W rating which technically would've slightly changed how the oils acted at operating temp vs 10w but even then not enough to make any difference.

With the new synthetics they're exactly the same at operating temp and the only difference is how they flow when cold.

https://bobistheoilguy.com/forums/threads/reason-to-not-use-5w-30-over-10w-30.158895/post-2335884

If I were in your shoes I'd just run 5w-30 all the time.

 

Thank you