diff --git a/src/charts/SingleSetAreaChart.tsx b/src/charts/SingleSetAreaChart.tsx
index 22477d6..b84d150 100644
--- a/src/charts/SingleSetAreaChart.tsx
+++ b/src/charts/SingleSetAreaChart.tsx
@@ -38,10 +38,12 @@ interface Props {
   multiGraphZoom?: (domain: number[] | string[]) => void;
   colourAboveZero?: ColourData
   colourBelowZero?: ColourData
+  minY?: string | number
+  maxY?: string | number
 }
 
 export default function SingleSetAreaChart(props: Props) {
-  const { data, maxRef, minRef, newXDomain, multiGraphZoom, yAxisLabel, colourAboveZero, colourBelowZero, tooltipLabel, tooltipUnit } = props;
+  const { data, maxRef, minRef, newXDomain, multiGraphZoom, yAxisLabel, colourAboveZero, colourBelowZero, tooltipLabel, tooltipUnit, minY, maxY } = props;
   const [xDomain, setXDomain] = useState<string[] | number[]>(["dataMin", "dataMax"]);
   const [refLeft, setRefLeft] = useState<number | undefined>();
   const [refRight, setRefRight] = useState<number | undefined>();
@@ -152,7 +154,8 @@ export default function SingleSetAreaChart(props: Props) {
           />
           <YAxis
             type="number"
-            domain={["auto", "auto"]}
+            allowDataOverflow
+            domain={[minY ?? "auto", maxY ?? "auto"]}
             label={{
               value: yAxisLabel,
               position: "insideLeft",
diff --git a/src/gate/GateDeltaTempGraph.tsx b/src/gate/GateDeltaTempGraph.tsx
index cad0564..4b498dd 100644
--- a/src/gate/GateDeltaTempGraph.tsx
+++ b/src/gate/GateDeltaTempGraph.tsx
@@ -210,7 +210,9 @@ export default function GateDeltaTempGraph(props: Props){
       }
       />
       <SingleSetAreaChart 
-        data={data} 
+        data={data}
+        minY={-40} //-40C is the same as -40F
+        maxY={(user.tempUnit() === pond.TemperatureUnit.TEMPERATURE_UNIT_FAHRENHEIT ? 104 : 40)}
         tooltipLabel="Delta Temp" 
         tooltipUnit={user.tempUnit() === pond.TemperatureUnit.TEMPERATURE_UNIT_FAHRENHEIT ? " °F" : " °C"} 
         yAxisLabel={"Delta T" + (user.tempUnit() === pond.TemperatureUnit.TEMPERATURE_UNIT_FAHRENHEIT ? " °F" : " °C")}