The patina color of Q355NH weathering steel screens does show subtle seasonal changes, but it is not obvious or unstable fading-it's a normal visual and physical reaction.
1. Why seasonal color changes happen
Humidity & moistureRainy / humid seasons (summer, rainy season) → patina absorbs water → looks darker, richer, deeper brown.Dry seasons (winter, dry autumn) → surface dry → looks slightly lighter, matte brown.
Temperature & oxidation rateWarm season → faster surface oxidation → slight darkening.Cold season → reaction slows → color basically stable.
Light & angleStrong summer sunlight → higher contrast → looks brighter brown.Weak winter light → looks darker and softer.
Air pollution / dustMore dust in winter / dry season → surface looks duller.Clean air after rain → color appears more vivid.
2. What it actually looks like
Summer / rainy season: darker, moist, deep chocolate brown
Winter / dry season: slightly lighter, matte, grayish brown
The difference is mild and visual, not real fading or damage.
3. When the change becomes obvious
If not sealed with a transparent coating
In places with very distinct dry‑wet seasons
In coastal or industrial environments
4. How to eliminate seasonal fluctuations
Apply a layer of matte transparent protective oil / clear coat-it isolates moisture and stabilizes color year‑round.
