Lawn jobs can be done for most of the year in the Mediterranean.
However there is a best time for certain jobs.
See lawn calendar for list of lawn jobs
Plugs can be planted at any time of year. But if expectations for growth are paramount, then plant grass plugs at the beginning of the season, when daily temperatures at 9.00 in the morning are constant at 15 degrees for at least 7 days.
Warm season seed will only germinate when temperatures are right. The best time for this is when the temperatures at 9.00 in the morning have been 18 degrees or more for at least 7 days.
Note: Substitute your own figures for best times in your area.