Most listings are in the $30's per square foot per year. The California region is going through a a boost in rates. In the last 3 months, the median rate went up $1 per sqft per year. That's a 2% rise in rent.
In the last 90 days, 9975 listings have come on the market, so you'll want to check back regularly for new listings. About 5% of the available leases in the California are subleases, so you will probably have to focus your search on direct office leases. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 2,560 sqft, there are still 0 new listings below 2,000 sqft. Most properties in this market are close to 2 floors. Most buildings in this market were built in 1960 and are Class B.