Above 72°F modeled soil
52.7% Too warm
17,686 ZCTAs
National fall field report August 29, 2026
The largest current group is too warm: 53% of covered U.S. ZCTAs.
The latest verified release places 17,686 of 33,565 covered ZCTAs in the modeled too warm to seed band for fall overseeding. The band is keyed to modeled 2–4 inch soil temperature, not the spring crabgrass GDD model. The report rebuilds daily from the same citable GDD release used by the public data product.
01
The national pulse
The current distribution across four modeled fall-timing bands
65–72°F modeled soil
38.8% Approaching
13,010 ZCTAs
50–65°F modeled soil
8.4% Open
2,807 ZCTAs
Below 50°F modeled soil
0.2% Closing
62 ZCTAs
The midpoint covered ZCTA is too warm to seed for fall overseeding.
The 10th–90th percentile modeled soil-temperature range across covered ZCTAs.
National median cumulative base-50 GDD from Jan. 1 in the same verified public release.
02
Reusable national image
State medians show how the fall window differs across the country
03
Twelve states to watch
The coolest state medians lead the fall window
01
Open
Alaska
Median 52.6°F modeled soil; 0.8% approaching, 74.7% open, and 91% cooling across 245 covered ZCTAs.
Open Alaska's overseeding tool02
Open
Vermont
Median 64.7°F modeled soil; 47.2% approaching, 52.8% open, and 89.4% cooling across 265 covered ZCTAs.
Open Vermont's overseeding tool03
Approaching
New York
Median 66.5°F modeled soil; 54.1% approaching, 28.6% open, and 99.8% cooling across 1,826 covered ZCTAs.
Open New York's overseeding tool04
Approaching
Wisconsin
Median 66.7°F modeled soil; 74.8% approaching, 25.2% open, and 99% cooling across 783 covered ZCTAs.
Open Wisconsin's overseeding tool05
Approaching
New Hampshire
Median 66.8°F modeled soil; 86.2% approaching, 13.4% open, and 89.4% cooling across 246 covered ZCTAs.
Open New Hampshire's overseeding tool06
Approaching
Michigan
Median 66.9°F modeled soil; 76.9% approaching, 23.1% open, and 98% cooling across 992 covered ZCTAs.
Open Michigan's overseeding tool07
Approaching
Pennsylvania
Median 67.7°F modeled soil; 70.9% approaching, 20.4% open, and 98.1% cooling across 1,833 covered ZCTAs.
Open Pennsylvania's overseeding tool08
Approaching
Minnesota
Median 68.3°F modeled soil; 81.9% approaching, 16% open, and 66.7% cooling across 880 covered ZCTAs.
Open Minnesota's overseeding tool09
Approaching
North Dakota
Median 68.5°F modeled soil; 83.3% approaching, 10.5% open, and 37.5% cooling across 389 covered ZCTAs.
Open North Dakota's overseeding tool10
Approaching
Ohio
Median 68.8°F modeled soil; 90.9% approaching, 0.1% open, and 98.2% cooling across 1,233 covered ZCTAs.
Open Ohio's overseeding tool11
Approaching
Rhode Island
Median 68.8°F modeled soil; 100% approaching, 0% open, and 100% cooling across 81 covered ZCTAs.
Open Rhode Island's overseeding tool12
Approaching
Maine
Median 68.9°F modeled soil; 86.9% approaching, 13.1% open, and 44% cooling across 427 covered ZCTAs.
Open Maine's overseeding toolRead this before seeding or treating
A modeled temperature is not a prescription
This report maps this site's operational overseeding and aeration bands. Those cut points are a broad planning cue for cool-season turf — not a universal, research-validated threshold for every grass species, seed blend, region, or application.
Modeled soil temperature is an estimate with roughly ±5°F expected error versus an in-ground thermometer, especially under snow, shade, unusual moisture, or local terrain. Before using any pesticide, read and follow the current label on your container; before buying seed, confirm the blend and rate your region supports. Product registrations and state restrictions can change.
EPA: how to read legally enforceable pesticide labels04
Fall pre-emergent is a different model
Not the spring crabgrass GDD window
Spring model
Crabgrass pre-emergents key to soil warming
This site's spring pre-emergent tool uses base-50 GDD accumulated from January 1 to time crabgrass and summer-annual products as soils warm. Nothing in this fall report uses those thresholds for fall products.
Fall model
Winter-annual pre-emergents key to soil cooling
Poa annua and other winter annuals germinate as soils cool. Extension guidance keys fall pre-emergent applications to modeled soil temperature dropping below about 70°F — the same signal this report publishes, not a GDD number.
Watch signal from this release
35.8% of covered ZCTAs currently sit at or below 70°F modeled soil. None should be treated yet — the signal is a prep cue for the northern tier and mountain states as soil temperatures keep falling, and it never overrides a product label or local Extension guidance.
Pre-emergents also block grass seed, so an overseeding plan changes what you can apply and when. Never apply a fall pre-emergent to an area you are seeding in the same season unless the label allows it.
05
All-state summary
Every state, the same verified public release
Status is assigned from each state's median ZCTA modeled soil temperature. The four count columns show the underlying within-state distribution so a median does not masquerade as a uniform state. GDD50 is season-warmth context from the same public release, not a fall application threshold.
| State | Median soil | 10th–90th pct. | Median GDD50 | Modeled status | Too warm | Approaching | Open | Closing | Cooling | Available ZCTAs |
|---|---|---|---|---|---|---|---|---|---|---|
| Alabama AL | 82.7°F | 78°F–84.7°F | 4,410.8 | Too warm | 656 | 0 | 0 | 0 | 97.1% | 656 |
| Alaska AK | 52.6°F | 46.8°F–56.6°F | 393.3 | Open | 0 | 2 | 183 | 60 | 91% | 245 |
| Arizona AZ | 91.2°F | 73.3°F–99°F | 5,428.8 | Too warm | 381 | 33 | 2 | 0 | 13.7% | 416 |
| Arkansas AR | 83.4°F | 80.6°F–85.5°F | 4,069.8 | Too warm | 614 | 0 | 0 | 0 | 96.1% | 614 |
| California CA | 78.7°F | 67.8°F–86.6°F | 3,685.9 | Too warm | 1,384 | 301 | 118 | 0 | 11.9% | 1,803 |
| Colorado CO | 73.7°F | 58.4°F–78.1°F | 2,290.8 | Too warm | 309 | 101 | 118 | 0 | 37.3% | 528 |
| Connecticut CT | 69.4°F | 66.6°F–71.1°F | 2,128.2 | Approaching | 18 | 270 | 0 | 0 | 100% | 288 |
| Delaware DE | 75°F | 74.3°F–75.4°F | 3,173.9 | Too warm | 67 | 1 | 0 | 0 | 100% | 68 |
| Florida FL | 84.2°F | 82.4°F–86.3°F | 5,628.1 | Too warm | 1,013 | 0 | 0 | 0 | 92.3% | 1,013 |
| Georgia GA | 81.6°F | 78.3°F–84.2°F | 4,154.3 | Too warm | 749 | 2 | 0 | 0 | 94.3% | 751 |
| Hawaii HI | 79.1°F | 61.6°F–83°F | 5,208.7 | Too warm | 84 | 0 | 12 | 1 | 14.4% | 97 |
| Idaho ID | 73°F | 65.6°F–78.9°F | 1,761.9 | Too warm | 156 | 98 | 26 | 0 | 9.3% | 280 |
| Illinois IL | 71°F | 68.5°F–75.5°F | 2,795.7 | Approaching | 534 | 859 | 3 | 0 | 99.7% | 1,396 |
| Indiana IN | 69.9°F | 67.7°F–74°F | 2,675.7 | Approaching | 172 | 635 | 0 | 0 | 98.3% | 807 |
| Iowa IA | 70.4°F | 67.9°F–72.8°F | 2,496.3 | Approaching | 180 | 790 | 0 | 0 | 94.8% | 970 |
| Kansas KS | 78.8°F | 74.7°F–83°F | 3,416.8 | Too warm | 703 | 1 | 0 | 0 | 96.3% | 704 |
| Kentucky KY | 73.3°F | 70.4°F–76.3°F | 3,186.7 | Too warm | 558 | 221 | 0 | 0 | 98.7% | 779 |
| Louisiana LA | 86.2°F | 84.4°F–87.7°F | 5,260.9 | Too warm | 539 | 0 | 0 | 0 | 73.1% | 539 |
| Maine ME | 68.9°F | 64.5°F–70.4°F | 1,763.5 | Approaching | 0 | 371 | 56 | 0 | 44% | 427 |
| Maryland MD | 73.6°F | 70.5°F–76.6°F | 3,064.3 | Too warm | 337 | 140 | 0 | 0 | 100% | 477 |
| Massachusetts MA | 69.4°F | 65.8°F–72.3°F | 2,115.3 | Approaching | 55 | 461 | 23 | 0 | 91.7% | 539 |
| Michigan MI | 66.9°F | 63°F–69.5°F | 2,073.1 | Approaching | 0 | 763 | 229 | 0 | 98% | 992 |
| Minnesota MN | 68.3°F | 63.8°F–70.7°F | 2,083.4 | Approaching | 18 | 721 | 141 | 0 | 66.7% | 880 |
| Mississippi MS | 84.1°F | 82.3°F–85.4°F | 4,658.4 | Too warm | 427 | 0 | 0 | 0 | 91.6% | 427 |
| Missouri MO | 75.6°F | 72.7°F–80.6°F | 3,283.9 | Too warm | 988 | 47 | 0 | 0 | 100% | 1,035 |
| Montana MT | 68.9°F | 62.3°F–74.2°F | 1,538.3 | Approaching | 89 | 198 | 82 | 0 | 6.8% | 369 |
| Nebraska NE | 73.1°F | 70.9°F–75.9°F | 2,741.4 | Too warm | 437 | 149 | 0 | 0 | 86.9% | 586 |
| Nevada NV | 79.7°F | 66.5°F–97.1°F | 3,016.1 | Too warm | 144 | 24 | 12 | 0 | 11.7% | 180 |
| New Hampshire NH | 66.8°F | 64.5°F–70.2°F | 1,904.3 | Approaching | 0 | 212 | 33 | 1 | 89.4% | 246 |
| New Jersey NJ | 72.3°F | 69.3°F–74.8°F | 2,820.6 | Too warm | 367 | 231 | 0 | 0 | 100% | 598 |
| New Mexico NM | 75.4°F | 62.2°F–86.1°F | 2,528.8 | Too warm | 254 | 45 | 74 | 0 | 23.9% | 373 |
| New York NY | 66.5°F | 63.1°F–73.5°F | 1,996.7 | Approaching | 315 | 988 | 523 | 0 | 99.8% | 1,826 |
| North Carolina NC | 77.6°F | 72.2°F–80.5°F | 3,699.2 | Too warm | 768 | 73 | 12 | 0 | 95% | 853 |
| North Dakota ND | 68.5°F | 65°F–70.9°F | 1,834.2 | Approaching | 24 | 324 | 41 | 0 | 37.5% | 389 |
| Ohio OH | 68.8°F | 67°F–71.9°F | 2,534.1 | Approaching | 111 | 1,121 | 1 | 0 | 98.2% | 1,233 |
| Oklahoma OK | 86.7°F | 83.8°F–91.4°F | 4,496.5 | Too warm | 644 | 0 | 0 | 0 | 74.4% | 644 |
| Oregon OR | 70°F | 62.3°F–74.6°F | 1,797.8 | Approaching | 111 | 227 | 90 | 0 | 45.6% | 428 |
| Pennsylvania PA | 67.7°F | 63.8°F–71.3°F | 2,290.2 | Approaching | 159 | 1,300 | 374 | 0 | 98.1% | 1,833 |
| Rhode Island RI | 68.8°F | 67.9°F–71.7°F | 2,196.6 | Approaching | 0 | 81 | 0 | 0 | 100% | 81 |
| South Carolina SC | 81°F | 78°F–85.3°F | 4,124.8 | Too warm | 418 | 6 | 0 | 0 | 96% | 424 |
| South Dakota SD | 71.4°F | 68.5°F–74°F | 2,249.3 | Approaching | 150 | 223 | 2 | 0 | 68.3% | 375 |
| Tennessee TN | 76.5°F | 73.3°F–81.2°F | 3,604.1 | Too warm | 595 | 42 | 1 | 0 | 96.4% | 638 |
| Texas TX | 89.1°F | 86.2°F–93°F | 5,304.2 | Too warm | 1,988 | 1 | 0 | 0 | 14% | 1,989 |
| Utah UT | 74.6°F | 63.2°F–82.9°F | 2,268.7 | Too warm | 184 | 70 | 45 | 0 | 20.7% | 299 |
| Vermont VT | 64.7°F | 61.4°F–67.6°F | 1,601.9 | Open | 0 | 125 | 140 | 0 | 89.4% | 265 |
| Virginia VA | 74.3°F | 68.4°F–77.3°F | 3,212.2 | Too warm | 617 | 269 | 17 | 0 | 99.9% | 903 |
| Washington WA | 68.9°F | 63.2°F–75.3°F | 1,644.3 | Approaching | 153 | 341 | 111 | 0 | 21% | 605 |
| West Virginia WV | 69.4°F | 63.4°F–75.7°F | 2,521 | Approaching | 161 | 482 | 95 | 0 | 95.7% | 738 |
| Wisconsin WI | 66.7°F | 63°F–69°F | 2,064.6 | Approaching | 0 | 586 | 197 | 0 | 99% | 783 |
| Wyoming WY | 71°F | 60.7°F–74.8°F | 1,852.4 | Approaching | 55 | 75 | 46 | 0 | 6.3% | 176 |
Need the values in a newsroom or analysis workflow? Download the CSV with soil temperatures, GDD context, aeration and pre-emergent shares, dates, and state-tool URLs.
06
Method & uncertainty
How the report was generated
Start with the verified public GDD release
Every GDD value derives from public release
2026-08-29,
identified by its SHA-256 checksum. It contains 33,642
nationwide ZCTA rows; this 50-state report includes
33,565 fresh values.
Model soil temperature from air temperature
Each ZCTA's 2–4 inch soil temperature is estimated from its station's daily NOAA Tmax/Tmin with an exponentially weighted lag model (alpha 0.25/day, 7-data-day trend). It is a modeled estimate, not an in-ground sensor reading, with roughly ±5°F expected error.
Use a freshness-aware station chain
Each ZCTA can consider up to 8 nearby candidates. The pipeline uses the nearest station with sufficiently fresh Tmax/Tmin data and falls back when a closer station is stale or incomplete — the same chain behind the public GDD release.
Classify with the site's own published tools
Fall overseeding status comes from the same soil-temperature logic as the overseeding tool: above 72°F is too warm, 65–72°F is approaching, and 50–65°F is the germination window. Aeration shares use the aeration tool's fall window (48–65°F). Fall pre-emergent readiness is a separate 70°F-and-falling watch signal — never the spring GDD model.
What the model cannot see
Elevation, coast and lake effects, urban heat, shade, snow cover, irrigation, soil moisture and texture, and turf condition all shift real soil temperatures. Recent GHCN-Daily records may lag and can later be replaced by archive-quality values. A station-based estimate is a planning proxy, not a measurement of an individual lawn.
Read the full site methodology07
Primary sources
Research and first-party guidance behind the framing
- Penn State Extension: overseeding turfgrass Fall establishment windows and seedbed preparation.
- University of Minnesota Extension: overseeding lawns Soil-temperature-gated late-summer/fall seeding guidance.
- Michigan State Extension: lawn management in early fall Fall seeding, aeration, and renovation sequence.
- Cornell Turfgrass Program: lawn renovation When core aeration and overseeding fit the cool-season cycle.
- University of Minnesota Extension: poa annua management Fall pre-emergent timing keyed to soil temperature cooling, not GDD.
- UW–Madison Turf: poa annua Winter-annual lifecycle and fall prevention windows.
- NOAA NCEI GHCN-Daily Daily station Tmax/Tmin and data-quality context.
- U.S. EPA pesticide labels Legally enforceable directions and restrictions.
From national signal to local check
Move from the national signal to your ZIP.
This stable report URL follows the latest verified daily release. The overseeding and aeration tools show the current modeled soil temperature, observation date, and station distance for a specific location.
Check your ZIP's fall overseeding status