I need a thermostat, which will control temperature regard the time. Temperature control must be ensured through proper thermostat_settings.

The temperature must be suitable for time this means that it must depends on date, hours, seasons of the year and office operations of course.

Date I mean months (January, February, ... , December) and days which are divided into workdays and weekend.
Workdays in office are Monday, Tuesday, Wednesday, Thursday and Friday. Weekend is Suturday and Sunday.
So actually I may summarized that current date is just today. 

We have four seasons in Australia summer, autumn, winter and spring then temperature in office must depends on these seasons. Summer months are January, February and December, 
autumn months are March, April and May, winter months are June, July and August and spring months are September, October and November.

Generally business operations take place on workdays in proper hours. Therefore if today is workday and the hour is between 9 am and 5 pm then the office operations are during bussines hours,
otherwise operations are not during bussines hours.

Finally I have to specify the thermostat_settings for particular seasons.
In spring for operations during bussines hours thermostat_settings should be 20 degrees for operations outside bussines hours temerature should be 15 degrees.
In summer for operations during bussines hours thermostat_settings should be 24 degrees for operations outside bussines hours temerature should be 27 degrees.
In autumn for operations during bussines hours thermostat_settings should be 20 degrees for operations outside bussines hours temerature should be 16 degrees.
In winter for operations during bussines hours thermostat_settings should be 18 degrees for operations outside bussines hours temerature should be 14 degrees.