diff --git a/radolan.go b/radolan.go
index 3d39c18dede51317b99de153cb212b8cf1c832a2..cfdce277ef9e790e2a712dd99dcd4ffead5b3424 100644
--- a/radolan.go
+++ b/radolan.go
@@ -60,9 +60,9 @@ import (
 type Composite struct {
 	Product string // composite product label
 
-	CaptureTime  time.Time
-	ForecastTime time.Time
-	Interval     time.Duration
+	CaptureTime  time.Time     // time of source data capture used for forcasting
+	ForecastTime time.Time     // data represents conditions predicted for this time
+	Interval     time.Duration // time duration until next forecast
 
 	Data [][]RVP6 // rvp-6 data for each point [y][x]