Radiation model which explains why it gets cold at night

A diagram showing the spectra of sun and earth

A diagram showing how the greenhouse mechanism works

A diagram showing how sunlight is transmitted through the atmosphere

http://www.nasa.gov/multimedia/videogallery/index.html?media_id=148836911
Video from NASA

http://wunderground.com Weather Underground
Lexington
History

http://weather-warehouse.com/WeatherHistory/PastWeatherData_LexingtonBluegrassArpt_Lexington_KY_January.html Weather Warehouse

100 years of data for Lexington