Make a table to record the temperatures, with time in one column and temperature in another column. This helps to see where the temperatures will be for the minimum and maximum temperatures.
Draw a vertical line intersecting a horizontal line in the lower-left corner of the graph paper. The lines should start about an inch from the edge of the paper and extend to nearly the edge of the paper.
Label the horizontal axis with the time intervals, evenly spaced. Ideally all of the time data points from the table should appear on the graph.
Label the vertical axis with the temperatures from the table, going from minimum to maximum. All of the labels on the temperature side should be evenly spaced as well.
Plot the data points on the graph by starting with the first set in the table. Find the correct time label on the horizontal axis, then go up until you reach the proper temperature for that time. Repeat with the remaining data points.
Draw a line by connecting the plotted data points from left to right. Be sure to connect all the points in order to form a continuous line.
Write a title for your line graph to make it easily identifiable in the future.