Soil Temperature in Honolulu, HI
Look up current soil and ground temperature readings for any U.S. ZIP code. We use USDA-NRCS soil monitoring station data to provide daily readings, historical trends, and lawn timing recommendations.
Soil Temps helps homeowners make confident lawn timing decisions using real soil temperature data. Enter your ZIP code to get planting windows, pre-emergent timing, fertilizer guidance, and disease watch alerts — all based on USDA sensor readings at your nearest monitoring station.
How Soil Temperature Drives Lawn Timing
Track how soil temperatures are trending at your location with daily readings and 12-month historical data. Unlike air temperature forecasts, soil temps change gradually — a sustained warming trend over several days is a stronger planting signal than any single reading. Enter your ZIP code above to see the current soil temperature trend and forecast for your area.
Soil temperatures — sometimes called ground temperatures — shift more slowly than air readings, making them a more reliable indicator of root zone conditions. When the 2-inch depth reaches germination thresholds for several consecutive days, weed seeds activate — that is your signal for pre-emergent timing. At 4-inch depth, sustained temperatures above 65°F indicate warm-season grass is actively growing and ready for fertilizer or aeration. Compare the planting window and recommendation guidance above with the daily chart below to make your decision.
About the Data
Readings refresh nightly from the USDA-NRCS Soil Climate Analysis Network. Planting windows are derived from multi-year climatology overlaid with NOAA 1991–2020 frost normals. Recommendation cards evaluate current soil conditions against research-backed thresholds from university extension sources. Check back regularly as conditions change — the guidance updates with every new reading.
Data sources: USDA-NRCS SCAN network, NOAA 1991–2020 climate normals, and localized frost climatology via Soil Temps analytics.
Browse soil temperature data by state — over 2,000 cities with current readings, hardiness zones, and planting windows.
Soil Temperature FAQ
What soil temperature is needed to plant grass seed?
Cool-season grasses like fescue and bluegrass germinate best when soil at 2 inches stays between 50–65°F for several consecutive days. Warm-season grasses like Bermuda and Zoysia need soil temperatures of 65–70°F or higher before seeding.
How deep should I measure soil temperature?
Measure at 2 inches for germination decisions — that is where seeds sit. For established lawn health, 4-inch readings indicate root-zone conditions and help time fertilizer, aeration, and disease prevention.
What’s the difference between soil temperature and air temperature?
Soil changes temperature much more slowly than air due to thermal mass. A warm afternoon does not mean the ground is warm. Soil temperature lags air temperature by days or weeks, making it a more reliable indicator of when biological processes like germination actually begin.
When should I apply pre-emergent based on soil temperature?
Apply pre-emergent herbicide when soil at 2 inches reaches 55°F for several consecutive days. This is the threshold where crabgrass and other summer annual weeds begin germinating. Applying after this point reduces effectiveness significantly.
What is a USDA Plant Hardiness Zone?
USDA Plant Hardiness Zones divide the US into 13 zones based on average annual extreme minimum temperature. They help determine which plants and grasses can survive winter in your area. Zone numbers increase from coldest (1a) to warmest (13b).