Identifying Highest Temperature from Line Graph

Below is a line graph showing the temperature in degrees Fahrenheit over a week:

Temperature Over a Week:

From the graph:

• Monday: 70°F
• Tuesday: 75°F
• Wednesday: 80°F
• Thursday: 77°F
• Friday: 72°F
• Saturday: 74°F
• Sunday: 78°F

What was the highest temperature recorded during the week?