diff --git a/src/lib.rs b/src/lib.rs
index 9ec9856..9c6d907 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -222,6 +222,20 @@ impl Config {
             }
         }
 
+        if config.sunset_start >= config.sunset_end {
+            return Err(ConfigError::InvalidTime(format!(
+                "sunset_start ({0}) is greater than sunset_end ({1})",
+                config.sunset_start, config.sunset_end
+            )));
+        }
+
+        if config.sunrise_start >= config.sunrise_end {
+            return Err(ConfigError::InvalidTime(format!(
+                "sunrise_start ({0}) is greater than sunrise_end ({1})",
+                config.sunrise_start, config.sunrise_end
+            )));
+        }
+
         Ok(config)
     }
 }