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 3:38 PM. The temperature feels like 35.400000000000006 with a humidity level of 70 so dress accordingly. Cloud coverage is 62 percent with visibility at 15.9 percent. Today’s UV index is 1, don’t forget the sunscreen if you need it! Today’s winds are traveling west-southwest at a speed of 6 MPH. At the end of the day don’t miss the sunset at 12:18 AM.