diff --git a/assets/src/scripts/monitoring-location/store/hydrograph-data.js b/assets/src/scripts/monitoring-location/store/hydrograph-data.js
index 216721a1dd8c238fa0fcb07fe99f40e7ab2faed3..4f412a42e2f7005fc716dd3f559fbaad24cdf50a 100644
--- a/assets/src/scripts/monitoring-location/store/hydrograph-data.js
+++ b/assets/src/scripts/monitoring-location/store/hydrograph-data.js
@@ -124,7 +124,7 @@ const retrieveIVData = function(siteno, dataKind, {parameterCode, period, startT
                         points: value.value.map(point => {
                             let pointValue = parseFloat(point.value);
                             pointValue = pointValue === noDataValue ? null : pointValue;
-                            if (pointValue && isCalculatedTemperatureCode) {
+                            if (pointValue !== null && isCalculatedTemperatureCode) {
                                 pointValue = parseFloat(convertCelsiusToFahrenheit(pointValue).toFixed(2));
                             }
                             return {
diff --git a/assets/src/scripts/monitoring-location/store/hydrograph-data.test.js b/assets/src/scripts/monitoring-location/store/hydrograph-data.test.js
index 8f01ffef070ecd7c8b2e13e75abc69d1d5cd440e..ba3944dbef3a85ee741e92b62ad7322f4aad22cd 100644
--- a/assets/src/scripts/monitoring-location/store/hydrograph-data.test.js
+++ b/assets/src/scripts/monitoring-location/store/hydrograph-data.test.js
@@ -390,8 +390,10 @@ describe('monitoring-location/store/hydrograph-data', () => {
                         description: 'Temperature, water, degrees Fahrenheit (calculated)',
                         unit: 'deg F'
                     });
+                    const values = hydrographData.primaryIVData.values['157775'].points.map(point => point.value);
+                    expect(values).toHaveLength(3);
+                    expect(values).toEqual([35.60, 32.00, 35.78]);
                 });
-
             });
         });
     });