ours is a country with tropical to HOT weather variations 8 months a year. freezing or below freezing temperatures happen in non-urban locations for 45 to 70 days tops.
engine oil is recommended based on location. 0-30 may be needed in Azad kashmir from October to February in a 1KR FE engine for quick start and better performance,
but the same car with same engine in Gawadar will be noisy & fuel hungry in the same time frame if 0 -30 is used. .. viscosity of oil is to ensure better lubrication at optimum temperatures.