Jefferson County, MO Sign Regulations: Window Signs (2026)

Section 400.4370(B) of the Jefferson County Code of Ordinances, part of the zoning code's sign article, sets the window-sign standard. A premises, or an occupant of a shopping center or multi-use building, may display permanent window signs covering no more than 15% of the window area of the building's facade. On top of that permanent allowance, the same location may add temporary window signs on an additional 15% of the facade, but only for up to 14 days within any 12 consecutive calendar months, tying the temporary allowance to a rolling annual window rather than a per-event basis.

The window-sign rule sits alongside other Article XIII sign standards adopted by Ordinance No. 16-0100 on January 4, 2016, which restructured the county's former street-graphics rules into the current sign article. Nearby provisions in the same section let a premises display one grand opening sign of up to 20 square feet and 8 feet in height for no more than 14 days in any 12-month period, and one directional sign per entrance or exit, sized 2 square feet on lower-speed two-lane roads or 4 square feet on higher-speed or multi-lane roads.

The county's zoning covers unincorporated Jefferson County; Arnold, Festus, De Soto, Hillsboro and the county's other incorporated cities enforce their own separate sign codes. Businesses wanting more flexibility than the standard limits allow, such as a coordinated storefront design, can instead submit a program for signs to the Planning Division under Section 400.4410, which can waive some numeric standards in exchange for a unified design reviewed for compatibility with the surrounding area.