I would think that a 10W30 (synth or conventional) would suit the OPer's climate just fine.
But, if you're switching grades looking for better NOACK, make sure that you're going to get it with the oil you choose.
The PQIA hasn't looked at a lot of synthetic 10W30s, and the only brand name I recognized in the bunch was Royal Purple with a NOACK loss of 9.8% (in 2011). This is a good result, but in the same range as synthetic 5W30s from RP (10.9%), M1 (10.1%), and QSUD (8.8%) in 2013.
Then you look at the PYB "conventional" 10W30 result from 2015 and see an amazingly low 4.4% NOACK loss! The PQIA was so shocked that they tested it again and correlated really well with 4.2%. There was a lot of discussion at the time about whether SOPUS was using GTL base stocks for this oil for some reason, but who know what was going on and what you'd get if you bought the same product (in its new bottle) now.
I can't find NOACK loss for M1 10W30, but I do notice that it has lower HTHS and 100C viscosities than M1 5W30...probably not what you'd be looking for in hot climate protection!
But, if you're switching grades looking for better NOACK, make sure that you're going to get it with the oil you choose.
The PQIA hasn't looked at a lot of synthetic 10W30s, and the only brand name I recognized in the bunch was Royal Purple with a NOACK loss of 9.8% (in 2011). This is a good result, but in the same range as synthetic 5W30s from RP (10.9%), M1 (10.1%), and QSUD (8.8%) in 2013.
Then you look at the PYB "conventional" 10W30 result from 2015 and see an amazingly low 4.4% NOACK loss! The PQIA was so shocked that they tested it again and correlated really well with 4.2%. There was a lot of discussion at the time about whether SOPUS was using GTL base stocks for this oil for some reason, but who know what was going on and what you'd get if you bought the same product (in its new bottle) now.
I can't find NOACK loss for M1 10W30, but I do notice that it has lower HTHS and 100C viscosities than M1 5W30...probably not what you'd be looking for in hot climate protection!