Device will be named thermostat. It must controll temperature according to the time.
It must allows to set temperature by option named thermostat_setting. Time will be represented by
date and hour. It must be considered also that temperature may vary on seasons of year and time in which operation is taken by thermostat.
Date will be represented by day and month. Current date may be named today also.

days: Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday.
months: January, February, March, April, May, June, July, August, September, October, November, December.
seasons: summer, autumn, winter, spring.

Logic of thermostat must allow to set when operation is during business hours or not during business hours 
e.g. for workdays time between 9 am and 5 pm operation is during business hours. Before 9 am and after 5 pm workday time and on weekend operation is not during business hours.
Of course interface must allow to define which days are workdays or weekend e.g.
for Monday, Tuesday, Wednesday, Thursday, Friday today is workday; for Saturday and Sunday today is weekend.

Also becouse in different countries particular seasons correspond to different months interface must allow to define months attributable to the season.
e.g.
for March, April, May it is winter,
for December, January, February season is summer.

In conclusion final configuration must allow to define different temperature depends on operation and season.
e.g.

For winter season and for operation during business hours thermostat_setting is 18 degrees.
For winter season and for operation not during business hours thermostat_settings is 14 degrees.