Costa Mesa, CA Sign Regulations: Window Signs (2026)

Article 3 of the sign chapter, section 13-115, adopts Table 13-115 to set the maximum allowed area, height, number, and other design restrictions for both permanent and temporary signs citywide. For permanent window signs the table requires a permit and limits coverage to 20% of contiguous window area maximum, though the Planning Division or Zoning Administrator can approve more if the merchandise on display genuinely cannot be shown within that limit; even with that allowance, the code caps combined permanent and temporary window signage at 50% of contiguous window area.

Temporary window signs need no permit, are capped at the same 20% baseline, and section 13-115 imposes a hard 60-day display limit that matches the definition in section 13-111: a temporary window sign is a non-illuminated sign placed on or behind a window for a period of time not in excess of 60 days, while anything displayed longer, including any illuminated window sign, is treated as a permanent window sign requiring the permit and running against the same area caps. Contiguous window area itself is a defined term: it is the total surface of a window or panes separated only by vertical or horizontal mullions that are three inches wide or less, so a storefront broken up by wide mullions, columns, or separate facades is measured window-by-window rather than as one combined total, which can tighten the effective cap on buildings with segmented glazing.

Because temporary window signs are exempt from permitting, the 60-day clock and the 20% area cap are the enforcement hooks the development services department relies on for retailers who leave sale banners or paper signage up indefinitely.