This shows county median home values divided by county median household income, both for 2023.
For example a score of "5" means the median home price in that county is 5 times the median household income in that county.
Generally, a score under 4 is considered affordable, 4-6 is pushing it, and over 6 is unaffordable for the median income.
There are of course other factors to consider such as property tax, down payment amount, assistance programs, etc. Property tax often varies at the city/township level so is impossible to accurately show.
Median Household Income Data is from US Census Bureau.
Median Home Value from National Association of Realtors, and Zillow/Redfin .
Home Values Data Link with map (missing data pulled from Zillow/Redfin/Realtor)
San Luis Obispo has like 50k people, not sure it's listed under 250k+ pop