Hilo, HI Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Hilo, Hawaii.
Gardening in Hilo
The Big Island's rainiest city sits on Hilo Bay, where volcanic soil and tropical rainfall create growing conditions that are essentially a year-round greenhouse.
Zone 10b with 364 frost-free days. Hilo gets 130+ inches of rain annually — the wettest city in the US. Tropical conditions grow food continuously. The volcanic soil from Kilauea is mineral-rich but sometimes too new to have developed organic matter.
Hilo's diverse community — Japanese, Filipino, Hawaiian, Portuguese — brings food traditions from across the Pacific. The Hilo Farmers Market is one of the most colorful and diverse in America.
What This Means for Hilo Gardeners
The average last spring frost in Hilo is around January 1, and the average first fall frost arrives around December 31. That gives you approximately 364 frost-free days to work with.
Hilo's growing season is essentially year-round. Frost is a rare event, not a seasonal boundary. Traditional cool-season crops grow through your mild winter, while tropical and subtropical plants thrive permanently outdoors. Your challenge isn't length of season — it's managing summer heat and humidity. Plant warm-season vegetables from September through February and shift to heat-tolerant crops for the summer months.
These dates are based on NOAA 30-year Climate Normal data for the Hilo area. Your actual frost dates could shift 2-3 weeks in either direction in any given year. Learn more about our data sources.
What to Grow in Hilo
With 364 frost-free days, Hilo can grow nearly anything — including tropical and subtropical plants that most of the country can only dream about. Your prime vegetable season runs from fall through spring; summer is for heat-lovers like okra, sweet potatoes, and peppers. Recommended starting points: cherry tomatoes, jalapeños, okra, sweet potatoes, basil, collard greens, tomatillos, and lemongrass.
See the full Hawaii planting guide for all 40 plants: Hawaii Planting Calendar. Or enter your zip code for exact planting dates personalized to Hilo.
More About Zone 10B
Hilo is in USDA Hardiness Zone 10B, which means average annual extreme minimum temperatures between 35°F to 40°F. View the full Zone 10B planting guide.
See the complete planting calendar for Hawaii: Hawaii Planting Calendar.
Other Cities in Hawaii
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Hilo area. They represent historical averages, not predictions. In any given year, the actual last frost could be 2-3 weeks earlier or later. Microclimates within Hilo (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
You can plant cool-season crops (lettuce, kale, broccoli) from December 31 through January 1 — your cool season is your primary vegetable season. Warm-season crops like tomatoes and peppers go out in early spring. Tropical plants grow year-round. Enter your zip code for exact dates for every plant.