diff --git a/rffit.c b/rffit.c
index e61949e..da7d48d 100644
--- a/rffit.c
+++ b/rffit.c
@@ -296,7 +296,7 @@ int main(int argc,char *argv[])
   int site_id=4171;
   float xmin,xmax,ymin,ymax;
   float xminsel,xmaxsel,yminsel,ymaxsel;
-  float x0,y0,x,y;
+  float x0=0.0,y0=0.0,x=0.0,y=0.0;
   double mjd,v,v1,azi,alt,rms=0.0,day,mjdtca=56658.0,altmin=0.0;
   float t,f,vtca,foffset=0.0;
   char c,nfd[32]="2014-01-01T00:00:00";
diff --git a/rfplot.c b/rfplot.c
index 9ae762e..e370dca 100644
--- a/rfplot.c
+++ b/rfplot.c
@@ -54,7 +54,7 @@ int main(int argc,char *argv[])
   int ix=0,iy=0,isub=0;
   int i0,j0,i1,j1,jmax;
   float width=1500;
-  float x,y,x0,y0;
+  float x=0.0,y=0.0,x0=0.0,y0=0.0;
   char c;
   char path[128],xlabel[128],ylabel[64],filename[32],tlefile[128];
   int sec,lsec,ssec;