Windshield Tint Law in Washington
The six-inch strip, the AS-1 line, and the clear UV film you are allowed across the whole windshield.
The short answer
You may run a tinted strip along the top six inches of the windshield, provided it is transparent and does not reach into the AS-1 portion. Separately, clear UV film that reduces or eliminates ultraviolet light may be applied across the entire windshield.
The two separate permissions
Subsection (5)(e) of RCW 46.37.430 does two different things in one paragraph, and they get conflated constantly.
| What | Where | Condition |
|---|---|---|
| Greater light reduction (a tinted strip) | Along the top edge only | Transparent, and not into the AS-1 portion or more than six inches from the top |
| Clear UV film | The whole windshield | Must reduce or eliminate ultraviolet light — it is a clear product |
What the AS-1 line is
AS-1 is a marking etched into the glass near the top of most windshields, part of the federal safety glazing standard the statute references. It marks the boundary of the area that has to stay clear for the driver's view. The statute gives you two boundaries — the AS-1 line, or six inches from the top — and the strip must respect them.
Look along the top edge of your windshield near the corner. If there is an AS-1 marking, that is your line.
The clear UV film is the underrated part
Most people asking about windshield film want the strip. The more useful permission is the second one: a clear film across the full windshield that cuts ultraviolet light is expressly allowed, because it is not reducing visible light transmission.
The windshield is the largest piece of glass in the car and the one you sit behind for the whole drive. UV is what fades a dashboard and what reaches your skin and your left arm on a long drive. A clear film does that job without touching the legal picture at all, which is the rare case in this trade where the useful answer and the legal answer point the same way.
Clear UV film is not heat film. It targets ultraviolet, which is not the same band as the infrared that makes a car hot. If heat is the goal, that is a conversation about the side and rear glass, and about ceramic film.
What is not permitted on a windshield
The prohibited materials in subsection (5)(g) apply here as they do anywhere else: no mirror finish, no red, gold, yellow or black film, and nothing brushed or sprayed on in liquid form.
Questions we get
Can I tint my whole windshield in Washington?
Not with a light-reducing film. You may apply clear film that reduces or eliminates ultraviolet light across the whole windshield, and a tinted strip only along the top.
How far down can the strip go?
Not into the AS-1 portion, and not more than six inches from the top of the windshield.
Where is the AS-1 line?
It is etched into the glass near the top of most windshields, usually visible near a corner.
Does clear UV film block heat?
Not meaningfully. Ultraviolet and infrared are different things. Clear UV film protects the interior and your skin; heat rejection is a different film on different glass.
Is a strip worth doing?
It helps with low sun on an eastbound or westbound commute. Whether it is worth it depends on your drive, and we will tell you if we think it is not.