diff --git a/addons/weather/functions/fnc_calculateRoughnessLength.sqf b/addons/weather/functions/fnc_calculateRoughnessLength.sqf
index 5112cf4ef5c..d14bb960622 100644
--- a/addons/weather/functions/fnc_calculateRoughnessLength.sqf
+++ b/addons/weather/functions/fnc_calculateRoughnessLength.sqf
@@ -19,8 +19,10 @@
 #define ROUGHNESS_LENGTHS [0.0002, 0.0005, 0.0024, 0.03, 0.055, 0.1, 0.2, 0.4, 0.8, 1.6]
 
 private _windSource = _this vectorDiff ((vectorNormalized wind) vectorMultiply 25);
-
-private _nearBuildings = count (_windSource nearObjects ["Building", 50]);
+private _nearBuildings = {
+    // Filter lights - fixes high roughness on airports (#6602)
+    str _x find "light" == -1
+} count (_windSource nearObjects ["Building", 50]);
 private _isWater = surfaceIsWater _windSource;
 
 if (_nearBuildings == 0 && _isWater) exitWith {