diff --git a/services/gdd_service.go b/services/gdd_service.go
index 19bef95132a78dbc7c753b04869b7b383278ca67..381e559868d8a3cc539556bf37edcefd4b443b19 100644
--- a/services/gdd_service.go
+++ b/services/gdd_service.go
@@ -59,10 +59,14 @@ func GetNormalValues(request models.GddRequest) models.GddResponse {
 		sliceDateInt = 0
 	}
 
-	for i := sliceDateInt; i < len(gs[0].MinTemps); i++ { //; i++ {
+	for i := sliceDateInt; i < len(gs[0].MinTemps)*2; i++ { //; i++ {
 		row := []float64{}
+		idx := i
+		if i >= len(gs[0].MinTemps) {
+			idx -= len(gs[0].MinTemps)
+		}
 		for j := 0; j < len(gs); j++ {
-			row = append(row, utils.CalculateSingleGdd(gs[j].MinTemps[i], gs[j].MaxTemps[i], product))
+			row = append(row, utils.CalculateSingleGdd(gs[j].MinTemps[idx], gs[j].MaxTemps[idx], product))
 			if request.Accumulate && i > sliceDateInt {
 				row[j] += rows[len(rows)-1][j]
 			}