GreenlyFrost dates and when to plant in Hawaii
United States
None of the 2 cities in Hawaii had frost in 2016–2025, so crops are planted by warmth and rain rather than by frost dates.
Frost dates by city in Hawaii
| City | Last spring frost | First autumn frost | Frost-free days | Climate zone | Tomato: window |
|---|---|---|---|---|---|
| Hilo | none in ten years | none in ten years | — | No frost in ten years | — |
| Honolulu | none in ten years | none in ten years | — | No frost in ten years | — |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
Weather by month in Hawaii
Across the 2 cities the warmest month is September (average days 27.8 … 28.6 °C) and the coldest February (average nights 19 … 20.8 °C). No city here averages below 0 °C at night in any month.
| Month | Day, °C | Night, °C | Rain, mm |
|---|---|---|---|
| January | 25.4 … 25.6 °C | 19.4 … 21.1 °C | 93 |
| February | 24.9 … 25.1 °C | 19 … 20.8 °C | 129 |
| March | 25.1 … 25.5 °C | 19.6 … 21.2 °C | 151 |
| April | 25.7 … 26.1 °C | 20.1 … 22 °C | 138 |
| May | 26 … 26.7 °C | 20.7 … 22.7 °C | 122 |
| June | 26.6 … 27.5 °C | 21.3 … 23.6 °C | 88 |
| July | 27.3 … 28 °C | 21.9 … 24.2 °C | 100 |
| August | 27.6 … 28.6 °C | 22.2 … 24.6 °C | 127 |
| September | 27.8 … 28.6 °C | 22.1 … 24.4 °C | 94 |
| October | 27.4 … 28.2 °C | 21.8 … 24 °C | 137 |
| November | 26.4 … 27 °C | 20.9 … 23.3 °C | 131 |
| December | 25.5 … 25.9 °C | 19.9 … 22 °C | 138 |
Day and night: the lowest … highest monthly average among the cities; rain: the middle city (ERA5 via Open-Meteo).
Other regions: United States
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Florida
- Georgia
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York State
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington State
- West Virginia
- Wisconsin
More about the United States
- Gardening in the United States: climate zones and crops by region
- United States: frost dates by city
- When to plant tomatoes in the United States
- When to plant cucumbers in the United States
- When to plant bell peppers in the United States
- When to plant peas in the United States
- When to plant garlic in the United States
- Gardening by country
