The current average 2-inch soil temperature across Hawaii is 70°F. Readings range from 54°F to 81°F, from 6 USDA and NOAA monitoring stations. Soil across Hawaii is right at the seasonal normal of 70°F for mid-August, based on 6 of 6 stations with historical records. Hawaii spans USDA hardiness zones 11a to 12b, warm-season grass country. Last updated August 16, 2026.
Summer conditions across Hawaii with soil averaging 70°F at 2 inches. Warm-season grasses are in peak growth; keep cool-season lawns mowed high and watered deep. The next application windows arrive in fall, starting with pre-emergent as soil falls back through 70°F.
For warm-season lawns (bermuda, zoysia, St. Augustine), the best time to plant grass seed in Hawaii is once 2-inch soil reaches 65°F and keeps rising, with a full growing season ahead; soil that warm arrives early in the year here, and the window closes as soil cools back through 65°F, typically around November 10.
Soil across Hawaii stays above the cool-season minimum of 50°F year-round, so the warm-season band is the constraint that matters. For a green lawn through winter, some homeowners overseed with ryegrass; the winter overseeding guide covers that timing.
Timing varies within Hawaii: your city page tracks the local window from its nearest station: see when to plant in Honolulu, when to plant in Kapolei or when to plant in Hilo. Readings current through August 16, 2026: Hawaii averages 70°F at 2 inches right now; the Current Planting Conditions section above reads that number against the season.
Typical dates are computed from historical 2-inch soil temperature averages at 6 monitoring stations in Hawaii; your own window depends on your nearest station's readings.
Historical 2-inch soil temperature normals for Hawaii: the median across 6 in-state stations with multi-year records. Any given year runs ahead of or behind these values; the live average at the top of this page shows where this year stands.
| Month | Average 2-inch soil temperature |
|---|---|
| January | 65°F |
| February | 65°F |
| March | 67°F |
| April | 67°F |
| May | 69°F |
| June | 71°F |
| July | 74°F |
| August | 74°F |
| September | 70°F |
| October | 68°F |
| November | 67°F |
| December | 65°F |
Grass seed germination
Grass seed germination temperatures across Hawaii. Soil warmth varies by location, so check a city page for the live reading and what germinates there now.
| Grass species | Seeding soil temp (2 in) | Days |
|---|---|---|
| Kentucky bluegrass | 50–65°F | 14-30 |
| Tall fescue | 50–65°F | 7-12 |
| Perennial ryegrass | 50–65°F | 5-10 |
| Fine fescue | 50–65°F | 7-14 |
| Bermudagrass | 75–90°F | 10-30 |
For root-zone timing (fertilizer, aeration, weed control), see the 4-inch soil temperature for Hawaii. For how wet the ground is versus normal, see soil moisture for Hawaii. See the Hawaii soil temperature map for the full station view.
| Station | 2" Temp | Last Reading |
|---|---|---|
| Kainaliu (Hawaii) | 81°F | 2026-08-16 |
| Kukuihaele (Hawaii) | 75°F | 2026-08-14 |
| Waimea Plain (Hawaii) | 72°F | 2026-08-16 |
| Silver Sword (Hawaii) | 54°F | 2026-08-16 |
| Mana House (Hawaii) | 67°F | 2026-08-16 |
| Puuwai Ranch (Hawaii) | 70°F | 2026-08-16 |
Current 2-inch readings grouped along Hawaii's north-to-south axis. Regional spread matters for timing: the warm end of the state can open an application window a week or more before the cool end.
| Region | Avg 2" Temp | Range | Stations |
|---|---|---|---|
| Northern Hawaii (Hawaii County) | 73°F | 72–75°F | 2 |
| Central Hawaii (Hawaii County) | 69°F | 67–70°F | 2 |
| Southern Hawaii (Hawaii County) | 67°F | 54–81°F | 2 |
| City | ZIP | Current Temp |
|---|---|---|
| Hilo | 96720 | 54°F |
| Hon | 96827 | 78°F* |
| Honolulu | 96801 | 76°F* |
| J B P H H | 96853 | 78°F* |
| Kahului | 96732 | 78°F* |
| Kailua Kona | 96740 | 81°F |
| Kapolei | 96707 | 77°F* |
| Lahaina | 96761 | 76°F* |
Modeled estimate where no monitoring station is within 75 miles; all other readings are measured at USDA and NOAA stations.
Spring broadleaf timing for St.
Nutsedge is a sedge, not a grass, which is why standard weed control fails.
Learn how to mix, calibrate, and spray liquid pre-emergent herbicide.
Check whether your soil is warm enough for the seed you bought: cool-season grass seeds into 50-65°F soil (tall fescue prefers 60°F and up), warm-season into 75-85°F.
The current average 2-inch soil temperature across Hawaii is 70°F. Readings range from 54°F to 81°F depending on location and elevation, from 6 USDA and NOAA monitoring stations. Soil across Hawaii is right at the seasonal normal of 70°F for mid-August, based on 6 of 6 stations with historical records.
Apply pre-emergent herbicide when soil at 2 inches reaches 55°F for several consecutive days. Timing varies across Hawaii, so check your city's page for station-specific readings and the pre-emergent timing recommendation.
Hawaii spans USDA hardiness zones 11a to 12b, warm-season grass country. For warm-season grasses (bermuda, zoysia), the window typically opens around March 16, based on historical 2-inch soil temperature averages at 6 in-state stations. Timing varies by location, so check your city's planting window for the dates specific to your area.