#month mean high low
 1   4.8  13.7  -2.7
 2   5.1  15.2  -0.7
 3   8.2  20.8   0.1
 4  14.8  27.5   3.3
 5  20.9  32.2   9.5
 6  22.5  34.0  12.8
 7  28.4  36.1  21.2
 8  28.7  36.7  21.9
 9  23.7  32.5  14.7
10  18.0  30.5   7.3
11  11.2  22.7   2.8
12   5.6  14.9  -0.8