Be sure to watch the tides and make sure that if you start a downwinder session that the tide is fairly far out, so that you have some beach area to land on. The water can come right up to the edge of the rocks at the railroad tracks at high tide.
4/3 wetsuit late spring, shorty to board shorts in late June through July and August. Water temp 50°F late spring to upper 60's°F in August (tide will effect this more than in Gorge). Air temps 50's to 70°F in spring and 70's to 90's°F in summer.
This is probably the best spot for beginners to do downwinders on Northerlies, due to the fact that the wind is side/sideonshore, meaning that the wind would most likely carry you back into shore (there are no guarantees though). Best for downwinders on Northerlies on a fairly low tide. The beach curves, making several directions sideshore.
Seattle, Tacoma airport. From I-5: taking exit 173 to Northgate Way and turning west. After crossing Meridian, Northgate Way becomes NW 105th Street and crosses Aurora Ave. N (Highway 99). Turn right on Greenwood Ave N. and left on NW 110th Street (look for the crosswalk lights above the street). After 6 blocks, NW 110th Street becomes NW Carkeek Park Road and winds down into the valley for 1/2 mile to the park entrance. Watch for the "rainbow-colored" Department of Parks sign on your left.