Frost Laws & Spring Thaw Weight Limits by State
How seasonal spring-thaw weight restrictions work, which states post them, the typical window, how much they cut, and where to find the order in effect right now. Interstates are usually exempt. Covers all 50 states and DC. Reference only, not legal advice.
24States with frost laws
Mar–MayTypical window
PostedDeclared each year
51Jurisdictions
This is a reference, not a live feed. Frost orders are declared and lifted every spring, so the dates and posted limits change each season. Before you load heavy on a state or county road in the thaw, check that state's current seasonal load restriction from its DOT. Each state page below links you there.
01
How it works
Soft roads, lighter loads, for a few weeks
Frost pushes moisture up under the pavement all winter. When it thaws from the top down in spring, that water is trapped and the roadbed loses strength. A loaded truck that the road carries fine in July can crack it in March. So the northern-tier and mountain states drop weight limits on their weaker roads for the thaw, usually a percentage cut on axle limits or a posted tonnage cap. The Interstates are built heavier and stay exempt. The limits live on the state, county, and local routes.
02
By state
Frost law rules for all 50 states and DC
Tap a state for the typical window, how much the limits drop, whether the Interstates are exempt, and the live source for the current order.
| State | Frost laws | Typical window |
|---|---|---|
| Alabama AL | None | No seasonal restrictions |
| Alaska AK | Seasonal limits | By region, roughly late February through June, set each year by frost depth and thaw |
| Arizona AZ | None | No seasonal restrictions |
| Arkansas AR | None | No spring-thaw frost season |
| California CA | None | No seasonal restrictions |
| Colorado CO | Seasonal limits | No statewide CDOT spring-thaw program on the state-highway system |
| Connecticut CT | None | No statewide spring-thaw program |
| Delaware DE | None | No statewide seasonal window |
| District of Columbia DC | None | No seasonal restrictions |
| Florida FL | None | No seasonal restrictions |
| Georgia GA | None | No seasonal restrictions |
| Hawaii HI | None | No seasonal restrictions |
| Idaho ID | Seasonal limits | Spring breakup season, roughly late February into May, declared by ITD section by section as frost leaves the ground |
| Illinois IL | Seasonal limits | No statewide IDOT spring-thaw program |
| Indiana IN | Seasonal limits | Declared by county highway departments each spring as the ground thaws, commonly late February through April and shifting every year |
| Iowa IA | Seasonal limits | Spring thaw, set locally for up to 90 days a year |
| Kansas KS | None | No seasonal restrictions |
| Kentucky KY | None | No seasonal restrictions statewide |
| Louisiana LA | None | No seasonal spring-thaw restrictions |
| Maine ME | Seasonal limits | Roads can be posted any time between November 15 and June 1, but the spring thaw is the heart of it, roughly late winter into spring |
| Maryland MD | None | No seasonal restrictions |
| Massachusetts MA | Seasonal limits | Roughly March into April or May, when frost leaves the road base |
| Michigan MI | Seasonal limits | Declared by MDOT frost zone each spring as the thaw moves north |
| Minnesota MN | Seasonal limits | By frost zone, roughly early March to mid-May, re-set every year |
| Mississippi MS | None | No seasonal spring-thaw restrictions |
| Missouri MO | None | No routine spring-thaw program |
| Montana MT | Seasonal limits | Spring thaw restrictions run on affected routes roughly February through May, declared by MDT district as roadbeds saturate |
| Nebraska NE | None | No statewide seasonal program |
| Nevada NV | Seasonal limits | Roughly February 1 to April 30 each year on NDOT-designated routes, set by NDOT's annual over-dimensional permit Letter of Instruction |
| New Hampshire NH | Seasonal limits | Spring thaw, roughly late February or March through April or May, set each year by NHDOT district engineers as frost leaves the road base |
| New Jersey NJ | None | No seasonal spring-thaw program |
| New Mexico NM | None | No seasonal restrictions |
| New York NY | Seasonal limits | Roughly late February or March into April or May, as frost leaves the road base |
| North Carolina NC | None | No seasonal restrictions |
| North Dakota ND | Seasonal limits | Roughly early March through April or May, declared route by route as frost leaves the sub-base |
| Ohio OH | Seasonal limits | Set locally as roads thaw, typically late February through spring and re-declared every year |
| Oklahoma OK | None | No seasonal spring-thaw restrictions |
| Oregon OR | Seasonal limits | No single statewide spring-thaw calendar |
| Pennsylvania PA | Seasonal limits | Roughly February 15 to April 15, the freeze/thaw period defined in PennDOT Publication 23 |
| Rhode Island RI | None | No statewide RIDOT spring-thaw program |
| South Carolina SC | None | No seasonal restrictions |
| South Dakota SD | Seasonal limits | Any time from February 15 to April 30 |
| Tennessee TN | None | No seasonal restrictions |
| Texas TX | None | No seasonal spring-thaw restrictions |
| Utah UT | Seasonal limits | No statewide UDOT spring-thaw program |
| Vermont VT | Seasonal limits | Mud season, roughly March through April into May, as frost leaves the ground |
| Virginia VA | None | No seasonal restrictions |
| Washington WA | Seasonal limits | No fixed statewide window |
| West Virginia WV | None | No formal statewide window |
| Wisconsin WI | Seasonal limits | Declared by WisDOT frost zone |
| Wyoming WY | Seasonal limits | Spring thaw restrictions typically hit in March and April, though exact dates ride on ground temperature and moisture and change every year |
Sources: state DOT seasonal weight / load restriction programs. Last reviewed July 2026. Seasonal orders change every spring and are declared per road — this page shows how the system works; confirm the current restriction with the state DOT before you rely on it.
Frost Law FAQ
What are frost laws or spring thaw restrictions?
Frost laws are seasonal weight limits. When frost leaves the ground in spring the roadbed goes soft, so northern and mountain states cut axle and gross weight limits on their state, county, and local roads for a few weeks to keep heavy trucks from breaking up the pavement. The reduction is usually a percentage off the normal axle limit or a posted tonnage cap on the affected routes.
When do frost laws take effect?
It changes every year. The state DOT declares the restriction when the thaw starts and lifts it when the road firms up, so the dates move with the weather. The window is often somewhere from late February or March into April or May, and it varies by frost zone within a state. Never assume last year's dates. Check the state's current order before you load heavy.
How do I find the current weight restriction?
Go to the state DOT's seasonal load restriction page. Most northern states run an interactive map or a route list showing which roads are posted and at what limit, and many offer email or text alerts and a phone hotline. That live source is the only thing that tells you the order in effect today, because this page cannot. Sign up for the alerts if you run that state in spring.
Do frost laws apply to the Interstates?
Almost never. The Interstate system is built to full weight standard, so the seasonal reductions apply to state highways, county roads, and local routes, not the Interstate mainline. If your whole run stays on the Interstate you are usually fine. The trouble starts on the state and county roads at each end of the trip, where the posted seasonal limits bite. Watch for the posted signs.
03
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