Update weather-app.py

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: omar-coderabbitai

weather-app.py

@@ -17,9 +17,17 @@ def get_temperature(city_name, api_key):
         return None
 
 def main():
-    api_key = "YOUR_API_KEY_HERE"  # Replace this with your OpenWeatherMap API key
+    import os
+    api_key = os.getenv('OPENWEATHER_API_KEY')
+    if not api_key:
+        print("Error: Please set the OPENWEATHER_API_KEY environment variable")
+        return
+
     city = input("Enter a major U.S. city: ").strip()
-    
+    if not city:
+        print("Error: City name cannot be empty")
+        return
+
     temp = get_temperature(city, api_key)
     if temp is not None:
         print(f"The current temperature in {city.title()} is {temp:.1f}°F.")