diff --git a/FHEM/32_SYSSTAT.pm b/FHEM/32_SYSSTAT.pm
index 3bcbb8a2e..bdffb5c36 100644
--- a/FHEM/32_SYSSTAT.pm
+++ b/FHEM/32_SYSSTAT.pm
@@ -345,7 +345,7 @@ SYSSTAT_GetUpdate($)
     }
   } elsif( AttrVal($name, "synologytemperature", 0) > 0 ) {
     my $temp = SYSSTAT_getSynoTemp($hash);
-    if( $temp > 0 && $temp < 200  ) {
+    if( $temp && $temp > 0 && $temp < 200  ) {
       if( AttrVal($name, "synologytemperature", 0) eq 2 ) {
           $temp = sprintf( "%.1f", (3 * ReadingsVal($name,"temperature",$temp) + $temp ) / 4 );
         }