diff --git a/agcs.html b/agcs.html
index cfbe5c4..ba33ab9 100644
--- a/agcs.html
+++ b/agcs.html
@@ -196,13 +196,22 @@ line-height:140%;
 	}
 
 	function updateWind() {
-		document.getElementById("windSpeed").innerHTML = zeroFilledDir + "/" + instantWindSpeed;
+		if (isNaN(zeroFilledDir)) {
+			document.getElementById("windSpeed").innerHTML = "NIL";
+		} else {
+			document.getElementById("windSpeed").innerHTML = zeroFilledDir + "/" + instantWindSpeed;
+		}
 	}
 
 	function updateAvgWind() {
-		updateWindDirection(avgWindDir);
-		document.getElementById("avgWindSpeed").innerHTML = avgWindDir + "/" + avgWindSpeed;
-		document.getElementById("avgWindGust").innerHTML = avgWindGustDir + "/" + avgWindGustSpeed;
+		if (isNaN(avgWindSpeed) || avgWindSpeed < 2) {
+			document.getElementById("avgWindSpeed").innerHTML = "CALM";
+			document.getElementById("avgWindGust").innerHTML = "CALM";
+		} else {
+			updateWindDirection(avgWindDir);
+			document.getElementById("avgWindSpeed").innerHTML = avgWindDir + "/" + avgWindSpeed;
+			document.getElementById("avgWindGust").innerHTML = avgWindGustDir + "/" + avgWindGustSpeed;
+		}
 	}
 
 	function invalidateDisplay() {
diff --git a/mobile.html b/mobile.html
index 9eddb71..ae11437 100644
--- a/mobile.html
+++ b/mobile.html
@@ -138,7 +138,11 @@ line-height:140%;
 
 	function updateWind() {
 		myDiv = document.getElementById("windSpeed");
-		newHtml = zeroFilledDir + "/" + instantWindSpeed;
+		if (isNaN(zeroFilledDir)) {
+			newHtml = "NIL";
+		} else {
+			newHtml = zeroFilledDir + "/" + instantWindSpeed;
+		}
 		if (newHtml != myDiv.innerHTML) {
 			myDiv.innerHTML = newHtml;
 			flashBackground(myDiv);
@@ -147,7 +151,12 @@ line-height:140%;
 
 	function updateAvgWind() {
 		myDiv = document.getElementById("avgWindSpeed");
-		newHtml = avgWindDir + "/" + avgWindSpeed;
+		if (isNaN(avgWindSpeed) || avgWindSpeed < 2) {
+			newHtml = "CALM";
+		} else {
+			newHtml = avgWindDir + "/" + avgWindSpeed;
+		}
+
 		if (newHtml != myDiv.innerHTML) {
 			myDiv.innerHTML = newHtml;
 			flashBackground(myDiv);
@@ -155,7 +164,11 @@ line-height:140%;
 		}
 
 		myDiv = document.getElementById("avgWindGust");
-		newHtml = avgWindGustDir + "/" + avgWindGustSpeed;
+		if (isNaN(avgWindSpeed) || avgWindSpeed < 2) {
+			newHtml = "CALM";
+		} else {
+			newHtml = avgWindGustDir + "/" + avgWindGustSpeed;
+		}
 		if (newHtml != myDiv.innerHTML) {
 			myDiv.innerHTML = newHtml;
 			flashBackground(myDiv);