How Do You Apply Rain Repellent to a Windshield?

How to apply rain repellent

The result depends on a clean, dry surface. Skip the prep and the product smears instead of bonding.

1. 1

   Clean and dry the glass

   Wash the windshield with a glass cleaner and buff it dry, so no film or grime is trapped under the repellent.

2. 2

   Apply to a section

   Spread the repellent on a small area with a cloth or applicator, using a thin, even layer rather than a soaking wet one.

3. 3

   Let it haze

   Wait for the product to haze over — usually a minute or two — so it bonds to the glass before you buff it.

4. 4

   Buff off

   Wipe the haze away with a clean, dry microfiber cloth, turning to a fresh face until the glass is clear.

How long rain repellent lasts

A rain repellent is a sacrificial layer — it wears off as the wipers and weather work over it. On a daily driver it typically lasts a few weeks to a couple of months, less in heavy rain and wiper use. The signal to reapply is the beading itself: when water stops beading and starts sheeting across the glass, the layer is gone.

Reapplying on top of a dirty windshield traps grime under the new layer, so the glass gets cleaned and dried again before each application. A coating that has gone patchy can be stripped with a diluted alcohol wipe and a clay bar before a fresh coat goes on.

Signs it is time to reapply

• Water sheets across the glass instead of beading up.
• The wipers seem to smear where they used to glide.
• Bugs and grime stick more than they did right after applying.
• A few weeks have passed in heavy rain and wiper use.

More questions about applying rain repellent