Hello can someone advise if i can hold my birthday party on 21st this month at 4pm and have like 20 people and bring our own BBQ

Physical distance is important, but virus dies more quickly in sunlight, like 2 minutes. As for the park, no problem!

Check federal way rules. Pierce county you can't have more than 5 people who don't live at your home

I dont see why not was at steele lake and there were lots of people gathering playing volleyball