SDCL § 1-5-2: Business and official acts permitted on holidays.

Any public or private business may be transacted or legal process or notices of any kind may be served or published on any of said days or next succeeding days designated herein as holidays, excepting Sundays, provided, that for good cause, a judge in whose court an action has been or is about to be brought, may endorse upon any process or notice permission to serve the same on Sunday, and if so endorsed, service thereof on Sunday shall be valid.