Teaching line graphs

I noticed that my students have a really difficult time understanding line graphs and how to read them. I decided to have us track the temperature in the morning and in the afternoon and display it on a line graph. After each month we looked at it to determine trends in the temperature. 

Students realized that the morning temperature was always colder than the afternoon. 

As winter cam, the line graph gradually overall went down, and as spring came, the temperature went up overall. 

When the temperature was about the same in the morning and afternoon we inferred that is was raining or cloudy that day, which caused the temperature not to change much throughout the day. 

 As we finished a page in classroom, I moved it to the hallway so we could experience the change over a long period of time.

By doing this, I didn't have to spend a week or more teaching line graphs, instead it was authentic instruction and application throughout the year that students were constantly exposed to.