diff --git a/src/components/datetime/DateTimeController.cpp b/src/components/datetime/DateTimeController.cpp
index f71911ef..4dc16329 100644
--- a/src/components/datetime/DateTimeController.cpp
+++ b/src/components/datetime/DateTimeController.cpp
@@ -127,7 +127,7 @@ const char* DateTime::MonthShortToStringLow(Months month) {
   return MonthsStringLow[static_cast<uint8_t>(month)];
 }
 
-const char* DateTime::DayOfWeekShortToStringLow() {
+const char* DateTime::DayOfWeekShortToStringLow() const {
   return DaysStringShortLow[static_cast<uint8_t>(dayOfWeek)];
 }
 
diff --git a/src/components/datetime/DateTimeController.h b/src/components/datetime/DateTimeController.h
index 4eddc5a7..81319d15 100644
--- a/src/components/datetime/DateTimeController.h
+++ b/src/components/datetime/DateTimeController.h
@@ -64,7 +64,7 @@ namespace Pinetime {
       const char* MonthShortToString() const;
       const char* DayOfWeekShortToString() const;
       static const char* MonthShortToStringLow(Months month);
-      const char* DayOfWeekShortToStringLow();
+      const char* DayOfWeekShortToStringLow() const;
 
       std::chrono::time_point<std::chrono::system_clock, std::chrono::nanoseconds> CurrentDateTime() const {
         return currentDateTime;