Here are the basic requirements:

• In the matrix, x direction indicates the year and y direction indicates the month (you can switch them if you like). Each cell indicates the corresponding month of a specific year.

• You need to visualize the maximum and minimum temperature by month in some way (e.g. you can use click to switch max or min temperature).

• When hovering mouse on each cell, a tip should appear to show the date and the temperature value.

• A legend is needed to show the mapping between colors and values.