Wedding guest dress - what is the appropriate length?

[CrazyLucky]

Thank you in advance for the help.  My sister-in-law is getting married in April at 5pm.  Her dress is ivory.  My MILs dress is blue and floor length with 3/4 sleeves.  The men are wearing suits, but not tuxes.  My SIL insists it is not a formal occasion.  They are planning to have cornhole during the time between the ceremony and the start of cocktail hour.  I don't know which of these details is relevant.  I would definitely prefer not floor length.  Is knee length or tea length ok?

[bethaboo]

I think either of those lengths are fine for an occasion where corn hole will also be played. Sounds like a fun wedding!

[Mrs.flang]

Typically mother of the bride/groom dresses are more formal than a regular guest.  You should be totally fine in knee length or tea length.  I would probably only wear floor length if it were black-tie optional or the men were wearing tuxes.