Winter is always the time I want to see most plays, and to me this picture just couldn’t be from any other time of year, despite the low backs of the dresses. Theatre is also definitely for seeing with friends and discussing at the interval, unlike other art forms.
I find the way these two women are shown intriguing too – there’s no suggestion that they’re pining for lost husbands in the trenches, or waiting to be viewed (unlike in Renoir’s theatre paintings), or otherwise doing anything besides expecting a good time.
At the theatre, by Prudence Heward, 1928. Image and more discussion here.