diff --git a/interpolator/include/interpolator.inc b/interpolator/include/interpolator.inc
index 96bd7d76a..7f3226041 100644
--- a/interpolator/include/interpolator.inc
+++ b/interpolator/include/interpolator.inc
@@ -127,7 +127,7 @@ integer         , intent(in), optional  :: vert_interp(:)
 character(len=*), intent(out), optional :: clim_units(:)
 logical,          intent(out), optional :: single_year_file
 
-character(len=64)            :: src_file
+character(len=128)            :: src_file
 !++lwh
 real(FMS_INTP_KIND_)         :: dlat, dlon
 !--lwh