Frost dates for Mauna Loa, HI
When the last spring frost and first fall frost usually come, and when to plant, from 30 years of NOAA weather records.
Last spring frost
April 12
typical year
Safe to plant
May 18
frost is over in 9 of 10 years
First fall frost
December 1
typical year
Growing season
235 days
frost-free, typical year
Frost watch this week
Tonight's and the next six nights' lows from the National Weather Service forecast for the station's location. Frost: 32°F or colder. Possible frost: 33–36°F, mostly in low spots on clear, still nights.
When to plant
Counted from this page's frost dates. Warm-season crops wait for the safe-to-plant date.
| Crop | Start indoors | Plant outside | Fall planting |
|---|---|---|---|
| Cool-season crops | |||
| Peas | – | Mar 15 – 29 | – |
| Spinach | – | Mar 1 – 22 | Oct 6 – 20 |
| Lettuce | – | Mar 15 – Apr 5 | Oct 6 – 20 |
| Radishes | – | Mar 15 – Apr 26 | Oct 20 – Nov 3 |
| Onions | – | Mar 15 – 29 | – |
| Potatoes | – | Mar 22 – Apr 5 | – |
| Carrots | – | Mar 22 – Apr 12 | Sep 8 – 22 |
| Beets | – | Mar 15 – 29 | Sep 22 – Oct 6 |
| Kale | Feb 1 – 15 | Mar 15 – 29 | Sep 22 – Oct 6 |
| Broccoli | Feb 1 – 15 | Mar 29 – Apr 12 | Sep 22 – Oct 6 |
| Cabbage | Jan 18 – Feb 1 | Mar 15 – 29 | Sep 22 – Oct 6 |
| Garlic | – | – | Oct 20 – Nov 10 |
| Warm-season crops | |||
| Tomatoes | Mar 23 – Apr 6 | May 18 – Jun 1 | – |
| Peppers | Mar 16 – 30 | May 25 – Jun 8 | – |
| Cucumbers | – | May 18 – Jun 8 | – |
| Zucchini | – | May 18 – Jun 15 | – |
| Pumpkins | – | May 18 – Jun 8 | – |
| Green beans | – | May 18 – Sep 22 | – |
| Sweet corn | – | May 18 – Jun 15 | – |
| Basil | Apr 13 – 27 | May 25 – Jun 1 | – |
Onions: from sets. Green beans: until 10 weeks before the first fall frost. Garlic: harvest next summer.
The year at a glance
Start indoors Plant outside Fall planting
The chance of frost, by date
| 1 year in 10 | Half of years | 9 years in 10 | |
|---|---|---|---|
| Spring frost after | May 18 | April 12 | March 13 |
| Fall frost before | November 9 | December 1 | January 7 |
Frost here means 32°F or colder. Read across: in 1 year in 10, spring frost carries on past the first date, which is why that date is the safe-to-plant date.
Hard freeze (28°F)
A hard freeze kills most garden plants, even hardy ones. The last one in spring usually comes around February 13 (March 13 in a late year), and the first one in fall around January 22.
Where these dates come from
NOAA weather station MAUNA LOA 5 NNE, HI US (USW00021514), 1991–2020 climate normals. It's the nearest station for 43 zip codes, all within 153 miles:
96704, 96708, 96710, 96713, 96719, 96720, 96725, 96726, 96727, 96728, 96729, 96732, 96737, 96738, 96740, 96742, 96743, 96748, 96749, 96750, 96753, 96755, 96757, 96760, 96761, 96763, 96764, 96768, 96770, 96771, 96772, 96773, 96774, 96776, 96777, 96778, 96779, 96780, 96781, 96783, 96785, 96790, 96793
33 of these zip codes are more than 30 miles from the station, so their real frost dates may differ by a week or more.
Planting dates follow common university extension advice; your local extension service can fine-tune them for your soil and microclimate.