There is no better time to install an irrigation system. There are several alternatives. Ground level sprinklers keep the plumbing out of sight. The disadvantage is that, as plants can grow, they can block the path of the spray, and some areas do not get watered. Pop-up sprinkler heads can help to avoid some of the obstructionist plants.
Overhead systems maximize coverage and minimize dry spots.
Unfortunately, they also become a part of your visible landscape. The disadvantage of all sprinkler alternatives is that precious water gets carried away with the wind. The use of drip irrigation and soaker hoses are the most down to earth approaches. Care should be taken to make sure that sufficient length of hose is used. Dry spots may otherwise develop.