The 5 double suns hanging below his chin are presumably the same months as those with higher positions (excluding the equinox month September), while the 5 double suns forming the 'walls' and 'floor' of the dark 'fish' constitute winter.

Summer has 150 days and so has winter. This pattern is enforced by there being 3 kinds of daysigns, 15 to the left and 15 to the right:

The number 3 and 5 are needed to explain the year. 3 * 5 = 15 days, a half-month. 24 such half-months = 360. 5 dark nights to add.

This is similar to the Mayan year:

"Within the Haab, there were 18 named 'months' of 20 days each, with a much-dreaded interval of 5 unlucky days added at the end."

"After five complete cycles totaling 2,920 days, the movement of Venus fill eight idealized years of 365 days each and come within hours of spanning 99 lunations."