Thematic precipitation map

Discussion created by mentaljoe on Jan 23, 2013
Latest reply on Feb 10, 2013 by jdollasin
I want to create a basic county-level thematic map showing the mean precipitation. I have the counties in polygons and meteorological stations in points with the measured precipitation.

The issue is that most of the counties are containing several points so I first need a mean from every point within a polygon. How do I perform such an operation? There are no fields in the points attribute table that links them to the polygon except their geographic location. There are approx. 60 polygons and 3200 points.