Average days on market by zip code.

There are three statistical types of average: mean, median and mode.   Therefore, perhaps you are requesting the mean days on the market?    

Which region are you interested in?

As a realtor, we are educated in determining property values much like appraisers.  One of the first lessons in the textbook teaches us that a zip code can hold many different neighborhoods - from low income to high end and everything in between. Different neighborhood have different "demand" among buyers.  The "supply" of homes that satisfies the potential buyers in a neighborhood is critical to its price and the number of days it takes to sell the home on the open market.  To review home values or market activity by average across an entire zipcode doesn't do enough to represent the homes in all the different neighborhoods.

This is why Zillow's Zestimate is often critisized. 

It would be more accurate to contact a real estate agent in the local area.  S/he can give you more specific information regarding the price range and neighborhoods you are most interested in.  Realtors provide this information for free. 

Also remember, real estate is also a seasonal market.  Most homes sell in the Spring and Summer months, and slow during the fall and winter.  This is pattern is annual

Elizabeth Socha
Century 21 Amber Realty
Torrance, CA