Grapes are normally planted in the spring months, before they come out of dormancy. In the United States this is usually between March and May. Most grape vine suppliers do not ship grape vines for planting past the last week of May.
Growers in colder climates will want to wait until temperatures are not bitterly cold. If grapes are planted too soon and temperatures rise and then fall drastically, the grapes can be susceptible to cold damage. A local agricultural extension agent or greenhouse can recommend what month is best for planting in a specific area. Grapes planted later in the year do not have the rate of growth that grapes will if planted earlier.