diff --git a/Dockerfile b/Dockerfile
index 7f94dc5..ff60305 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -51,7 +51,7 @@ FROM ${NODE_VERSION}
 
 RUN apk add --no-cache tzdata
 ENV TZ=Europe/Prague \
-    LANG=cs_CZ.UTF-8 \
+    LC_ALL=cs_CZ.UTF-8 \
     NODE_ENV=production
 
 WORKDIR /app
diff --git a/Dockerfile-Woodpecker b/Dockerfile-Woodpecker
index 6d57a41..6291b32 100644
--- a/Dockerfile-Woodpecker
+++ b/Dockerfile-Woodpecker
@@ -4,7 +4,7 @@ FROM ${NODE_VERSION}
 
 RUN apk add --no-cache tzdata
 ENV TZ=Europe/Prague \
-    LANG=cs_CZ.UTF-8 \
+    LC_ALL=cs_CZ.UTF-8 \
     NODE_ENV=production
 
 WORKDIR /app
diff --git a/server/src/utils.ts b/server/src/utils.ts
index e8e8e35..aadacba 100644
--- a/server/src/utils.ts
+++ b/server/src/utils.ts
@@ -1,5 +1,7 @@
 import { Choices, LocationKey } from "../../types";
 
+const DAY_OF_WEEK_FORMAT = new Intl.DateTimeFormat(undefined, {weekday: 'long'});
+
 /** Vrátí datum v ISO formátu. */
 export function formatDate(date: Date, format?: string) {
     let day = String(date.getDate()).padStart(2, '0');
@@ -15,7 +17,7 @@ export function getHumanDate(date: Date) {
     let currentDay = String(date.getDate()).padStart(2, '0');
     let currentMonth = String(date.getMonth() + 1).padStart(2, "0");
     let currentYear = date.getFullYear();
-    let currentDayOfWeek = date.toLocaleDateString("CZ-cs", { weekday: 'long' });
+    let currentDayOfWeek = DAY_OF_WEEK_FORMAT.format(date);
     return `${currentDay}.${currentMonth}.${currentYear} (${currentDayOfWeek})`;
 }