Tulip bulbs are typically planted in the fall, specifically from September to December in northern climates, as they require a period of cold dormancy to bloom in the spring. The soil temperature should ideally be 60 degrees Fahrenheit or cooler. This allows the bulbs to establish roots before the ground freezes in winter, preparing them for a vibrant bloom when warmer temperatures return in the spring. However, the exact timing can vary depending on your specific geographical location and local climate conditions. It's always beneficial to consult with a local gardening expert or extension service to determine the best time to plant tulip bulbs in your area.