diff --git a/R/DTRRef.R b/R/DTRRef.R
index 008a993f825d1e1aabb0e486d27e38f2ba06471f..f275ddca810a4446ba059370797159588df39547 100644
--- a/R/DTRRef.R
+++ b/R/DTRRef.R
@@ -99,12 +99,12 @@ DTRRef <- function(tmax, tmin, by.seasons = TRUE, dates = NULL, timedim = NULL,
     dim_names <- names(dim(tmax))
   }
   if (is.null(dates)) {
-    dates.max <- attr(tmax, 'Variables')$common$time
-    if (is.null(dates.max)) {
+    dates.tmax <- attr(tmax, 'Variables')$common$time
+    if (is.null(dates.tmax)) {
       dates.tmax <- attr(tmax, 'Variables')$dat1$time
     }
-    dates.min <- attr(tmin, 'Variables')$common$time
-    if (is.null(dates.min)) {
+    dates.tmin <- attr(tmin, 'Variables')$common$time
+    if (is.null(dates.tmin)) {
         dates.tmin <- attr(tmin, 'Variables')$dat1$time
     }
     if (length(dates.tmax) != length(dates.tmin)) {