diff --git a/crabfit-frontend/src/components/AvailabilityViewer/AvailabilityViewer.jsx b/crabfit-frontend/src/components/AvailabilityViewer/AvailabilityViewer.jsx
index 7b5c74f..25008f4 100644
--- a/crabfit-frontend/src/components/AvailabilityViewer/AvailabilityViewer.jsx
+++ b/crabfit-frontend/src/components/AvailabilityViewer/AvailabilityViewer.jsx
@@ -112,7 +112,7 @@ const AvailabilityViewer = ({
                       onMouseEnter={e => {
                         const cellBox = e.currentTarget.getBoundingClientRect()
                         const wrapperBox = wrapper?.current?.getBoundingClientRect() ?? { x: 0, y: 0 }
-                        const timeText = timeFormat === '12h' ? `h${locales[locale].separator ?? ':'}mma` : `HH${locales[locale].separator ?? ':'}mm`
+                        const timeText = timeFormat === '12h' ? `h${locales[locale]?.separator ?? ':'}mma` : `HH${locales[locale]?.separator ?? ':'}mm`
                         setTooltip({
                           x: Math.round(cellBox.x-wrapperBox.x + cellBox.width/2),
                           y: Math.round(cellBox.y-wrapperBox.y + cellBox.height)+6,