Scatterplot is a simple graph that follows x and y coordinates.
Once you have the name of the cities, you can look up their latitude either using a printed map or online map, and that will be your x coordinate.
For your y coordinate, that will be the predicted temperature.
For example, the latitude of the Detroit is 42 degrees North (x coordinate) and has a temperature of 52 degree Fahrenheit (y coordinate), then we can have this plotted like this: (disregard the yellow line, it is only there as basis)
Another example: This is for Albuquerque. The latitude is 35.2 (x coordinate) and it's predicted temperature today is 73 degree Fahrenheit (y coordinate).
The red dot on the image above, that is where we will plot Albuquerque since it's latitude is 35.2 and its temperature is 73, as shown by the yellow lines. (Do not draw the yellow lines. It is only there for basis.)
You do the same with the rest of the cities using its corresponding latitude and predicted temperature today.