If you planning to travel to Costco Headquarters, Issaquah, Washington, here is your 6-day travel weather forecast to make sure you have all the essentials needed during your stay. Start your day when the sunrises at 2:01 PM. The temperature feels like 57.35 with a humidity level of 86 so dress accordingly. Cloud coverage is 61 percent with visibility at 12.8 percent. Today’s UV index is 2, don’t forget the sunscreen if you need it! Today’s winds are traveling south-southwest at a speed of 9 MPH. At the end of the day don’t miss the sunset at 1:54 AM.