On average, listings lease in the $20's per square foot per year. The Temecula region is experiencing a decrease in rates. In the last 3 months, the median rate fell $4 per sqft per year. That's a 16% decrease in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Temecula submarket has lower rates, so you should have no trouble finding a great deal in this discounted region.
In the last 90 days, 40 listings have come on the market, which means leases most likley are leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 15% of the listings in the Temecula are subleases, so you might be able to find a shorter term or below market rent. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,750 sqft. Most properties in this region are approximately 2 floors. Most buildings in this market were built in 1991 and are Class B.