I haven’t seen a thread re: summer work for this year, but here is a thread from last year –
Some unified auditions for summer stock, internships, or apprenticeships are: Midwest Theatre Auditions (MWTA), Straw Hats, Southeastern Theatre Conference (SETC), and New England Theatre Conference (NETC). Students who will graduate this year and available for year-round work can attend the Unified Professional Theatre Auditions (UPTA).
Companies often also hold local auditions. f you have questions about any of these auditions, ask away!