SurveyUSA polled 520 likely voters in King County; the poll has a margin of error of 4.4%:
Dan Satterberg (R): 43%
Bill Sherman (D): 49%
Among males, Satterberg leads Sherman 51% to 40%. But among females, Sherman leads Satterberg 58% to 35%. Oh…and females make up 52% of voters.
Sherman leads in all age, generation and race groups except for the 65+ crowd who prefer Satterberg.
The crosstabs are available here.
Update: I want to preempt the inevitable right wing spin about the fact that the poll results are slightly “within the margin of error.”
Statistically, the meaning of these results is this: if the election were held today, Sherman would win with a 93% probability and Satterberg would win with a 7% probability.