diff --git a/src/components/analytics/heatmap.tsx b/src/components/analytics/heatmap.tsx
index 531133c..44aa098 100644
--- a/src/components/analytics/heatmap.tsx
+++ b/src/components/analytics/heatmap.tsx
@@ -82,7 +82,7 @@ export function LotteryHeatmap() {
     setGeneratedSet([])
   }, [lottoType, timeframe, activeGame.max])
 
-  const maxFreq = Math.max(...numbers.map(n => n.frequency), 1)
+  const maxFreq = numbers.reduce((max, n) => Math.max(max, n.frequency), 1)
 
   const getTemperatureColor = (freq: number) => {
     const ratio = freq / maxFreq