The graph provides information about the temperature in Chicago between Sunday and Saturday. As an overall trend, it is clear that the temperature in Chicago was at increased dramatically on Monday and that it started to fell quickly in the middle of the week before rise swiftly again at the end of the week.
On Sunday, the temperature in Chicago stood at 25 ̊C. That temperature rose dramatically to 28 ̊C on Monday and then decreased slowly to 26 ̊C on Tuesday, went down steadily to 22 ̊C on Wednesday. At this point the temperature fell rapidly to 19 ̊C until on Thursday before boomed steadily to 23 ̊C on Friday and climbed swiftly to 27 ̊C on Saturday.
In conclusion, the graph indicates that temperature was increased dramatically on Monday, declined little by little and dropped quickly until on Thursday, then went up hugely the end of the week.