Americans enjoy entertaining guests outdoors, most commonly in the backyards of their homes, weather permitting of course. If the event occurs during the daytime, especially in summer, most people will be wearing decidedly casual clothing, especially if swimming is involved. An evening event may be less casual. Even if the event is casual, it is always wise as an outsider to wear neat, clean summer clothes, and avoid ultra-casual clothing like tank tops and sweat pants.
As with any other invitation where food is involved, you may ask if you can bring something and bring a small gift like wine even if the hosts say “no.”
Be prepared at an outdoor summer party to participate in some outdoor games and light sports. Choose a suitable pair of shoes. Participants (and these may be children) may begin throwing a Frisbee around, kicking a soccer ball, or organizing a game like volleyball or badminton. No one expects you to know all the rules, or have any particular skill at the game, in order to “join in.”
At outdoor events in which it is obvious that the party is going on behind the house, it is not impolite to join the party directly through a side yard door rather than ringing the front door of the house.
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