diff --git a/src/ds323x/datetime.rs b/src/ds323x/datetime.rs
index 74523f3..3491ea7 100644
--- a/src/ds323x/datetime.rs
+++ b/src/ds323x/datetime.rs
@@ -93,8 +93,13 @@ where
 
     fn month(&mut self) -> Result<u8, Self::Error> {
         let data = self.iface.read_register(Register::MONTH)?;
-        let value = data & !BitFlags::CENTURY;
-        Ok(packed_bcd_to_decimal(value))
+
+        let century = data & BitFlags::CENTURY;
+        if century != 0 {
+            return Err(Error::InvalidDeviceCentury);
+        }
+
+        Ok(packed_bcd_to_decimal(data))
     }
 
     fn year(&mut self) -> Result<u16, Self::Error> {
diff --git a/tests/datetime.rs b/tests/datetime.rs
index eb465c3..ec88bdf 100644
--- a/tests/datetime.rs
+++ b/tests/datetime.rs
@@ -185,12 +185,6 @@ mod month {
     get_param_test!(get, month, MONTH, 1, 1);
     read_set_param_test!(set, set_month, MONTH, 12, 0b0000_0010, 0b0001_0010);
     set_invalid_param_range_test!(invalid, set_month, 0, 13);
-
-    mod keeps_century {
-        use super::*;
-        get_param_test!(get, month, MONTH, 12, 0b1001_0010);
-        read_set_param_test!(set, set_month, MONTH, 12, 0b1000_0010, 0b1001_0010);
-    }
 }
 
 mod year {