Seattle is the answer there to avoid the CA state tax, cheaper rent / cost of living. Check levels.fyi for entry level SDE1 jobs / salaries. $160-190K USD total comp. Rent (usually your biggest expense) for a studio / 1BR is about 1.5-2K/mo. Tax brackets are quite different (that entry level job might push you into the 32% marginal rate, while in AU, that would be the 45% marginal bracket).
Mid career you could be earning 3-6x your Aussie salary post tax (depending on the exchange rates, life choices etc.), particularly if you find yourself earning significantly more due to stock appreciation.
Ah, but the weather... yes, I know it doesn't rain as much as people think (I've been there at all times of year) but it is awfully dark for awfully many hours in the winter.
Mid career you could be earning 3-6x your Aussie salary post tax (depending on the exchange rates, life choices etc.), particularly if you find yourself earning significantly more due to stock appreciation.