diff --git a/indra/newview/llvosky.cpp b/indra/newview/llvosky.cpp
index 66ba6249d3a135fb2d2b279b01a0cc54e4b3da32..3a94b03a84ddb132c9dfc42f3c2b4d060d569b1c 100644
--- a/indra/newview/llvosky.cpp
+++ b/indra/newview/llvosky.cpp
@@ -754,7 +754,7 @@ void LLVOSky::calcSkyColorWLVert(LLVector3 & Pn, LLColor3 & vary_HazeColor, LLCo
 {
 	// project the direction ray onto the sky dome.
 	F32 phi = acos(Pn[1]);
-	F32 sinA = sin(F_PI - phi);
+	F32 sinA = llmax(sin(F_PI - phi), 0.01f);
 	F32 Plen = dome_radius * sin(F_PI + phi + asin(dome_offset_ratio * sinA)) / sinA;
 
 	Pn *= Plen;