diff --git a/promql/functions.go b/promql/functions.go
index f02262ac40..2cb90a9b6c 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -848,7 +848,7 @@ func funcAvgOverTime(_ []Vector, matrixVal Matrix, args parser.Expressions, enh
 			var (
 				sum                  = s.Histograms[0].H.Copy()
 				mean, kahanC         *histogram.FloatHistogram
-				count                float64
+				count                = 1.
 				incrementalMean      bool
 				nhcbBoundsReconciled bool
 				err                  error