Meredith
Your API key is not activated yet. Remember that newly created API keys will need ~ 15 minutes to be activated and show data, so you might see an API error in the meantime.
Or
Invalid API key. Please see http://openweathermap.org/faq#error401 for more info.
Or
Invalid API key. Please see http://openweathermap.org/faq#error401 for more info.