USDA Hardiness Zone 9B covers southern Florida, the lower Rio Grande Valley, and parts of coastal Southern California, with average annual minimum temperatures between 25°F and 30°F. The growing season stretches to approximately 298 frost-free days, from a last spring frost around Feb 15 to a first fall frost near Dec 10. With nearly ten months of frost-free weather, Zone 9B allows gardeners to grow subtropical crops and maintain production nearly year-round. The coolest months — December through February — are prime time for leafy greens, root vegetables, and brassicas. For a personalized forecast based on your specific zip code, use our free planting calendar. Browse individual plant guides for detailed growing instructions, or explore how USDA zones work to better understand your growing conditions.