So here's the short version: GSM matters, but it's not the whole story. For California commutes, lighter tees (150–170) are your best bet for heat and comfort. Heavier ones (200+) are for colder days or when you want a sturdier feel. Don't get stuck on the number—get the tee that matches your day.

And remember, no shirt is 'premium' just because it's heavy. Look at the details, feel the fabric, and pick what works for you. That's the kind of advice I'd give across the counter—and now you've got it.

This guide is for general shopping advice only. Always check the product page for current specs and care instructions.