Mr. Widmer is completing his first four-year term and Mr. DeGolia was elected to a one-year term last year to fill the seat left vacant when Jerry Carlson moved from Atherton.
The two other candidates have experience in Atherton town government. Ms. Hau, an architect, is vice chair of the Civic Center Advisory Committee and Mr. Lempres, an attorney, is a member of the town's transportation and rail committees.
The council now has only four members. Jim Dobbie, whose term was to expire in November, resigned earlier this year due to poor health, and his unfilled seat is one of the three that voters will fill this fall. Mr. Dobbie died July 24.