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Frost Law Tracker
Frost laws are seasonal weight restrictions imposed on roads during spring thaw. They typically reduce legal weight limits by 20"“50% from February through May across the northern US and Canada. Use this tracker to monitor active restrictions and get alerts when frost laws activate or lift in your corridors.
Live spring weight restriction status for US states and Canadian provinces. Get push alerts when frost laws activate or lift in your corridors.
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Push + email notifications when frost laws activate or lift in states you monitor. Free for all HC users.
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MN
WATCHMinnesota
Typical: Mar 1 "“ May 15 · Reduction: 50%
Early spring thaw expected March 2026.
WI
WATCHWisconsin
Typical: Mar 1 "“ May 1 · Reduction: 50%
Statewide frost map updated weekly.
MI
WATCHMichigan
Typical: Feb 15 "“ Apr 30 · Reduction: 35%
MI Upper Peninsula typically 2 weeks earlier.
ND
CLEARNorth Dakota
Typical: Mar 15 "“ May 15 · Reduction: 50%
Frost laws not yet posted for 2026.
SD
CLEARSouth Dakota
Typical: Mar 15 "“ May 1 · Reduction: 50%
SDDOT posts restrictions on state DOT site.
IA
CLEARIowa
Typical: Mar 1 "“ Apr 15 · Reduction: 35%
Iowa DOT 511 posts real-time county restrictions.
IL
CLEARIllinois
Typical: Feb 15 "“ Apr 15 · Reduction: 20%
IDOT issues county-level frost restrictions.
IN
CLEARIndiana
Typical: Mar 1 "“ Apr 15 · Reduction: 25%
INDOT enforces by district.
OH
CLEAROhio
Typical: Mar 1 "“ Apr 30 · Reduction: 25%
ODOT posts district-level weight restrictions.
PA
CLEARPennsylvania
Typical: Feb 15 "“ Apr 15 · Reduction: 25%
PennDOT posts statewide frost maps.
NY
CLEARNew York
Typical: Mar 1 "“ Apr 30 · Reduction: 25%
NYSDOT enforces by county.
ME
CLEARMaine
Typical: Mar 15 "“ May 15 · Reduction: 50%
MaineDOT enforces spring postings April"“May.
ON
CLEAROntario (CA)
Typical: Mar 1 "“ Apr 30 · Reduction: 50%
MTO Spring Load Restriction (SLR) period.
AB
CLEARAlberta (CA)
Typical: Mar 1 "“ May 1 · Reduction: 35%
Alberta Transportation posts load restrictions.
SK
CLEARSaskatchewan (CA)
Typical: Mar 15 "“ May 1 · Reduction: 50%
Sask Highways posts spring road bans.
MB
CLEARManitoba (CA)
Typical: Mar 15 "“ May 1 · Reduction: 50%
Manitoba Infrastructure posts spring road restrictions.
Frost Law FAQs
What is a frost law?+
Frost laws (also called spring weight restrictions or spring road bans) are seasonal weight limits imposed on roads when the ground is thawing after winter. As frost leaves the ground, the road base weakens and heavy loads cause severe pavement damage. Weight limits are typically reduced 20"“50% during frost law periods.
When do frost laws start and end?+
Frost laws typically begin February"“March and lift by April"“May depending on latitude and weather. Minnesota and Michigan have the longest seasons. Exact dates vary year to year based on temperature and soil conditions — check this tracker for current status.
Can I still move oversize loads during frost laws?+
Yes, but loads must comply with reduced weight limits. A load that was legal before frost law season may need additional permits or routing changes when restrictions are active. Check with your permit agent.
How much are weight limits reduced during frost laws?+
Reductions vary by state: 20"“25% in Pennsylvania and Ohio, 35% in Michigan and Alberta, and up to 50% in Minnesota and Saskatchewan. Some restrictions apply only to certain road classes (local, county) rather than interstate highways.
Content last updated: April 2026 · Data verified against state DOT sources · Updated hourly during active frost law season