diff --git a/src/main/java/de/doubleslash/keeptime/App.java b/src/main/java/de/doubleslash/keeptime/App.java
index 2c3ff0a3..1abc87ec 100644
--- a/src/main/java/de/doubleslash/keeptime/App.java
+++ b/src/main/java/de/doubleslash/keeptime/App.java
@@ -21,9 +21,11 @@
 import java.io.StringWriter;
 import java.time.LocalDate;
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.stream.Collectors;
 
+import de.doubleslash.keeptime.common.DateFormatter;
 import javafx.stage.Window;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -84,6 +86,8 @@ public class App extends Application {
    @Override
    public void init() throws Exception {
       LOG.info("Starting KeepTime.");
+      DateFormatter.setSystemLocale(Locale.getDefault());
+      Locale.setDefault(Locale.ENGLISH);
       final DefaultExceptionHandler defaultExceptionHandler = new DefaultExceptionHandler();
       defaultExceptionHandler.register();
 
diff --git a/src/main/java/de/doubleslash/keeptime/common/DateFormatter.java b/src/main/java/de/doubleslash/keeptime/common/DateFormatter.java
index 5b876a24..da6eda52 100644
--- a/src/main/java/de/doubleslash/keeptime/common/DateFormatter.java
+++ b/src/main/java/de/doubleslash/keeptime/common/DateFormatter.java
@@ -16,15 +16,23 @@
 
 package de.doubleslash.keeptime.common;
 
+import javafx.scene.control.DatePicker;
+import javafx.util.StringConverter;
+
 import java.time.Duration;
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.time.format.FormatStyle;
+import java.util.Locale;
 
 public class DateFormatter {
    private static DateTimeFormatter dayDateFormatter = DateTimeFormatter.ofPattern("eeee dd.MM.yyyy");
    private static DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern("HH:mm:ss");
 
+   private static Locale systemLocale = Locale.getDefault();
+
    private DateFormatter() {
       throw new IllegalStateException("Utility class: DateFormatter");
    }
@@ -55,4 +63,36 @@ public static String toTimeString(final LocalDateTime localDateTime) {
       return localDateTime.format(timeFormatter);
    }
 
+   public static void setSystemLocale(Locale locale) {
+      systemLocale = locale;
+   }
+
+   public static Locale getSystemLocale() {
+      return systemLocale;
+   }
+
+   public static void applySystemLocaleOnDate(DatePicker datePicker) {
+      DateTimeFormatter formatter = DateTimeFormatter.ofLocalizedDate(FormatStyle.SHORT).withLocale(systemLocale);
+
+      datePicker.setConverter(new StringConverter<>() {
+         @Override
+         public String toString(LocalDate date) {
+            return (date != null) ? formatter.format(date) : "";
+         }
+
+         @Override
+         public LocalDate fromString(String s) {
+            try {
+               return (s != null && !s.isEmpty()) ? LocalDate.parse(s, formatter) : null;
+            } catch (DateTimeParseException e) {
+               return null;
+            }
+         }
+      });
+
+      datePicker.setOnShowing(e-> Locale.setDefault(Locale.Category.FORMAT, systemLocale));
+      datePicker.setOnHiding(e-> Locale.setDefault(Locale.Category.FORMAT, Locale.getDefault()));
+      datePicker.setOnAction(e-> Locale.setDefault(Locale.Category.FORMAT, Locale.getDefault()));
+      datePicker.setPromptText(formatter.format(LocalDate.now()));
+   }
 }
diff --git a/src/main/java/de/doubleslash/keeptime/view/ExternalProjectsSyncController.java b/src/main/java/de/doubleslash/keeptime/view/ExternalProjectsSyncController.java
index 0f6dac2f..e472b9af 100644
--- a/src/main/java/de/doubleslash/keeptime/view/ExternalProjectsSyncController.java
+++ b/src/main/java/de/doubleslash/keeptime/view/ExternalProjectsSyncController.java
@@ -124,7 +124,9 @@ public class ExternalProjectsSyncController {
    private final Color colorLoadingSuccess = Color.valueOf("#74a317");
    private final Color colorLoadingFailure = Color.valueOf("#c63329");
 
-   private final LocalTimeStringConverter localTimeStringConverter = new LocalTimeStringConverter(FormatStyle.MEDIUM);
+   private final LocalTimeStringConverter localTimeStringConverter = new LocalTimeStringConverter(
+         FormatStyle.MEDIUM,
+         DateFormatter.getSystemLocale());
    private ObservableList<TableRow> items;
 
    private LocalDate currentReportDate;
@@ -579,8 +581,10 @@ private void showErrorDialog(List<String> errorMessages) {
    }
 
    private void setUpTimeSpinner(final Spinner<LocalTime> spinner) {
+      final LocalTimeStringConverter stringConverter = new LocalTimeStringConverter(
+            FormatStyle.MEDIUM,
+            DateFormatter.getSystemLocale());
       spinner.focusedProperty().addListener(e -> {
-         final LocalTimeStringConverter stringConverter = new LocalTimeStringConverter(FormatStyle.MEDIUM);
          final StringProperty text = spinner.getEditor().textProperty();
          try {
             stringConverter.fromString(text.get());
@@ -621,7 +625,7 @@ public void increment(final int steps) {
 
       });
 
-      spinner.getValueFactory().setConverter(new LocalTimeStringConverter(FormatStyle.MEDIUM));
+      spinner.getValueFactory().setConverter(stringConverter);
    }
 
    public static LocalTime decrementToLastFullQuarter(LocalTime time) {
diff --git a/src/main/java/de/doubleslash/keeptime/view/ManageWorkController.java b/src/main/java/de/doubleslash/keeptime/view/ManageWorkController.java
index b9455b93..db8f1bfa 100644
--- a/src/main/java/de/doubleslash/keeptime/view/ManageWorkController.java
+++ b/src/main/java/de/doubleslash/keeptime/view/ManageWorkController.java
@@ -21,6 +21,7 @@
 import java.time.format.DateTimeParseException;
 import java.time.format.FormatStyle;
 
+import de.doubleslash.keeptime.common.DateFormatter;
 import javafx.scene.control.skin.ComboBoxListViewSkin;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -120,6 +121,9 @@ private void initialize() {
 
    private void setUpTimeRestriction() {
 
+      DateFormatter.applySystemLocaleOnDate(startDatePicker);
+      DateFormatter.applySystemLocaleOnDate(endDatePicker);
+
       BooleanBinding isValidBinding = Bindings.createBooleanBinding(() -> {
          if (startTimeSpinner.getValue() == null || endTimeSpinner.getValue() == null
                || startDatePicker.getValue() == null || endDatePicker.getValue() == null) {
@@ -150,8 +154,11 @@ private void setUpTimeRestriction() {
    }
 
    private void setUpTimeSpinner(final Spinner<LocalTime> spinner) {
+      final LocalTimeStringConverter stringConverter = new LocalTimeStringConverter(
+            FormatStyle.MEDIUM,
+            DateFormatter.getSystemLocale()
+            );
       spinner.focusedProperty().addListener((e) -> {
-         final LocalTimeStringConverter stringConverter = new LocalTimeStringConverter(FormatStyle.MEDIUM);
          final StringProperty text = spinner.getEditor().textProperty();
          try {
             stringConverter.fromString(text.get());
@@ -188,7 +195,7 @@ public void increment(final int steps) {
 
       });
 
-      spinner.getValueFactory().setConverter(new LocalTimeStringConverter(FormatStyle.MEDIUM));
+      spinner.getValueFactory().setConverter(stringConverter);
 
    }
 
diff --git a/src/main/java/de/doubleslash/keeptime/view/ReportController.java b/src/main/java/de/doubleslash/keeptime/view/ReportController.java
index 5d714518..3933cbd6 100644
--- a/src/main/java/de/doubleslash/keeptime/view/ReportController.java
+++ b/src/main/java/de/doubleslash/keeptime/view/ReportController.java
@@ -355,14 +355,13 @@ private void updateReport(final LocalDate dateToShow) {
 
    private void loadCalenderWidget() {
       final DatePicker myDatePicker = new DatePicker(this.currentReportDate);
+      DateFormatter.applySystemLocaleOnDate(myDatePicker);
       myDatePicker.valueProperty().addListener((observable, oldvalue, newvalue) -> {
          LOG.info("Datepicker selected value changed to {}", newvalue);
          updateReport(newvalue);
       });
 
-      // HACK to show calendar from datepicker
-      // https://stackoverflow.com/questions/34681975/javafx-extract-calendar-popup-from-datepicker-only-show-popup
-      final DatePickerSkin datePickerSkin = new DatePickerSkin(myDatePicker);
+
       final Callback<DatePicker, DateCell> dayCellFactory = callback -> new DateCell() {
          @Override
          public void updateItem(final LocalDate item, final boolean empty) {
@@ -378,9 +377,19 @@ public void updateItem(final LocalDate item, final boolean empty) {
 
       };
       myDatePicker.setDayCellFactory(dayCellFactory);
-      final Node popupContent = datePickerSkin.getPopupContent();
-      this.topBorderPane.setRight(popupContent);
 
+      Locale defaultLocale = Locale.getDefault();
+      try {
+         Locale.setDefault(DateFormatter.getSystemLocale());
+
+         // HACK to show calendar from datepicker
+         // https://stackoverflow.com/questions/34681975/javafx-extract-calendar-popup-from-datepicker-only-show-popup
+         final DatePickerSkin datePickerSkin = new DatePickerSkin(myDatePicker);
+         final Node popupContent = datePickerSkin.getPopupContent();
+         this.topBorderPane.setRight(popupContent);
+      } finally {
+         Locale.setDefault(defaultLocale);
+      }
    }
 
    private Button createDeleteWorkButton(final Work w) {
diff --git a/src/test/java/de/doubleslash/keeptime/common/DateFormatterTest.java b/src/test/java/de/doubleslash/keeptime/common/DateFormatterTest.java
index f3f63b6f..2c081465 100644
--- a/src/test/java/de/doubleslash/keeptime/common/DateFormatterTest.java
+++ b/src/test/java/de/doubleslash/keeptime/common/DateFormatterTest.java
@@ -18,12 +18,17 @@
 
 import static org.hamcrest.MatcherAssert.assertThat;
 
+import java.time.LocalDate;
 import java.time.LocalDateTime;
+import java.util.Locale;
 
+import javafx.scene.control.DatePicker;
 import org.hamcrest.Matchers;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
 @Disabled
 class DateFormatterTest {