Tried searched but seems to get different answers. Not asking what type of oil I should use but rather the ambient temp range for 15 - 40 oil.

I am using Penngrade1 15-40 now and recently temperature drops down to mid 30s to mid 40s in the morning.

Wondering if this will be too cold for 15 - 40 oils?

Thanks

 

Here's a temp table for oil from Motor State, a parts distributor. You'll have to convert degrees C to F. (As you probably know, Mazda recommends 5W-30 for below freezing only, and 10W-30 for all temps of about -15F or warmer, which does not quite correspond with the temps for those weights as shown in this table. I think Mazda is being conservative about the lower limits and prefers to see a thinner oil used in colder situations.)

:

https://www.motorstate.com/oilviscosity-htm/