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US Soil Temperature Map: Monthly Averages by Region

2-inch soil temperature is the single most important measurement in lawn care. Pre-emergent timing, seed germination, dormancy break, summer stress, and overseeding windows are all driven by soil temperature thresholds, not air temperature. Below are typical monthly soil temperatures across the major US lawn-care regions, plus the critical thresholds for each major decision. For your specific ZIP, use the live tool.

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Critical Soil-Temperature Thresholds

Every major lawn decision in spring orbits one of these six soil-temperature numbers. Use the regional tables below to estimate when each threshold typically arrives in your area.

  • 50°

    Pre-emergent trigger

    Apply crabgrass pre-emergent when 2-inch soil temperature reaches 50 to 55 deg F for three consecutive days, before crabgrass germinates.

  • 55°

    Cool-season seed germination starts

    Kentucky bluegrass, tall fescue, fine fescue, and perennial ryegrass germinate reliably at 55 deg F and rising.

  • 60°

    Warm-season green-up begins

    Bermuda, zoysia, and St. Augustine break dormancy and start producing chlorophyll around 60 deg F.

  • 65°

    Warm-season seed germination

    Bermudagrass, centipede, and bahiagrass seed germinate reliably above 65 deg F.

  • 75°

    Cool-season seeding cutoff

    Above 75 deg F, cool-season seed germination becomes unreliable and seedlings die from heat stress before establishing.

  • 85°

    Cool-season dormancy stress

    Above 85 deg F, cool-season grasses go into summer stress / semi-dormancy. Reduce mowing, raise blade height, water deeply.

Monthly Soil Temperature by Region

Ordered south-to-north (earliest to latest spring warm-up). Soil temperatures shown are 2-inch depth daily averages typical for the region. Your specific lawn may run a few degrees warmer or cooler depending on sun exposure, soil type, and microclimate.

Southeast

Southeast - Warm Season

March
50-65°F
April
60-75°F
May
65-80°F
June
70-85°F
July
75-90°F
September
65-80°F

Mid-Atlantic

Mid-Atlantic - Transition Zone

March
40-50°F
April
50-60°F
May
55-70°F
June
60-75°F
July
65-80°F
September
55-70°F

Central

Central - Transition Zone

March
40-50°F
April
50-60°F
May
60-70°F
June
70-80°F
July
75-85°F
September
65-75°F

Northeast

Northeast - Cool Season

March
35-45°F
April
45-55°F
May
50-65°F
June
55-70°F
July
60-75°F
September
50-65°F

Mountain West

Mountain West - Cool Season

March
35-45°F
April
45-55°F
May
55-65°F
June
65-75°F
July
70-80°F
September
55-65°F

Great Lakes

Great Lakes - Cool Season

March
35-45°F
April
45-55°F
May
55-65°F
June
60-70°F
July
70-80°F
September
60-70°F

Upper Midwest

Upper Midwest - Cool Season

March
30-40°F
April
40-50°F
May
50-60°F
June
60-70°F
July
70-80°F
September
55-65°F

Methodology

Monthly soil temperatures are 2-inch depth daily averages typical for each region, derived from NOAA station observations and cross-referenced against university extension turfgrass research (Penn State, Clemson, UGA, UF/IFAS, U Minnesota, U Missouri, Colorado State, Texas A&M). Regional averages are not a substitute for your specific microclimate; soil under full sun runs 3 to 5 degrees warmer than soil under tree shade in the same yard, and well-drained sandy soil warms faster in spring than heavy clay. For per-ZIP daily soil temperature with 5- and 10-year historical averages, use the live soil temperature tracker. Last reviewed 2026-05-15.

How to use soil temperature for lawn decisions

  1. Pick your decision. Pre-emergent? Cool-season seed? Warm-season green-up? Each has a soil-temp trigger in the threshold reference above.
  2. Look up your region's typical timing. Find your region in the monthly table; the row tells you when soil temperature crosses each threshold in a typical year.
  3. Verify with current data. Spring conditions vary year-to-year by 2 to 4 weeks. Pull current soil temp for your ZIP from the tracker before applying anything.
  4. Track a 5-day rolling average, not a single reading. A single warm day can spike soil temp by 5 degrees without changing the underlying trend. Wait for three consecutive days above the trigger before acting.
  5. Adjust for microclimate. South-facing slopes and sandy soils run warmer; tree-shaded and clay-soil areas run cooler. Apply pre-emergent to the warm parts of the lawn first.

Frequently Asked Questions

What is the most important soil temperature for lawn care?

The 55 degree Fahrenheit 2-inch soil temperature is the single most important threshold in lawn care. It triggers crabgrass pre-emergent application (apply at 50 to 55 deg F), starts reliable cool-season seed germination (Kentucky bluegrass, tall fescue, ryegrass), and signals the start of active warm-season grass growth recovery in the South. Most major lawn decisions in spring orbit this number.

How do I measure soil temperature at my lawn?

Insert a soil thermometer (any kitchen meat probe works) 2 inches deep into your lawn, wait 60 seconds, and read the temperature. Measure in mid-morning when soil temperature is closest to the daily average. Take 3 to 4 readings in different spots and average them. For lawn-care decisions you actually want the 5- to 7-day average, not a single reading, so use a ZIP-based tool that pulls historical data rather than guessing from one stab in the ground.

What is the difference between soil temperature and air temperature?

Soil temperature lags air temperature by about 1 to 3 weeks in spring and runs cooler overall. While air temperature swings 20 to 30 degrees between day and night, soil at 2-inch depth varies only 5 to 10 degrees daily. This is why soil temperature is a better signal for plant-biology decisions than air temperature: it captures what the seed or root is actually experiencing, not what the lawn surface looks like during a warm afternoon.

Why 2 inches and not deeper?

The 2-inch depth is the standard reference for turfgrass decisions because that is where most grass seed, crabgrass seed, and pre-emergent herbicide actions take place. Deeper measurements (4-inch, 6-inch) are used for agricultural planting decisions (corn, soybeans) where the seed is buried deeper. For lawn care, every university extension recommendation uses 2-inch soil temperature.

When does my soil temperature reach 50 degrees in spring?

Soil temperature hitting 50 degrees Fahrenheit varies by 8 to 10 weeks across the US. The Southeast and Gulf Coast typically hit 50 deg by mid-February; the Mid-Atlantic and Central transition zone by mid-March; the Northeast by late March to early April; the Great Lakes by mid-April; and the Upper Midwest by late April to early May. Use the regional table below for your specific climate, or check the live ZIP-aware tool for the current reading.

Cite this page

Free to cite and link to. Suggested citation:

What Grass Is This? (2026). "US Soil Temperature Map: Monthly Averages by Region." Available at: https://whatgrassisthis.com/soil-temperature-map

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