According to the projected weather reports the 21st is going to be raining though this weekend is supposed to be sunny. It was snowing at higher elevations (Clear Lake area) yesterday. If you want to drive up the McKenzie for fall colors, they are there now, mostly above Rainbow (about 49 miles from Eugene) and moving down in elevation.
Some people don’t mind driving in snow and some people don’t want to get wet. If this fits you, then you may want to consider an alternative activity for October 21st (The McKenzie River Field Trip).
Regardless of when you go, check the latest road conditions by calling 511. The road conditions can also be checked via Web Cam at: http://www.northwestwebcams.com/oregon-web-cams.shtm#road.