Average temperature for Oct. 9-11 is 32 degrees during the coldest part of the night and 63 degrees by day. Go to the 14 day forecast for South Lake Tahoe.
Tahoe typically has warm days and cold nights/mornings.
At the 8AM marathon start line you should expect temperatures in the 40's or low 50's for Oct 9-11 start. If a cold snap comes in down into the 30's. 24 years ago we had a 24 degreee start line.
By the afternoon temperature will be in the 60's or even the 70's. Some October years we have had temperatures in the 80's.
So that wasn't much of a help, so the answer is be prepared. You will be able to toss your race bag in a trailer or under the bus and it will be waiting for you at the finish line.
Tahoe Blue Vodka will have a nice clear bag with drawstring for you. Pick it up at packet pickup and put your race number and last name on it.
Your last name is critical as all the bags will look alike.