I-15 Road Conditions & Weather

I-15 runs 1,433 miles south to north from San Diego, California to Sweet Grass, Montana, crossing 6 states. Its longest stretch is 401 miles across Utah; its shortest is 29 miles in Arizona.

It climbs Cajon Pass at 3,777 ft, where the weather at the summit is not the weather on the approach.

Mile markers count from each state's southern line and start again at the next one, which is how most states number their exits as well. They are measured along the same road geometry these pages draw, so they land within a mile or two of the posted markers. A toll road that runs its own continuous numbering is the exception — on the New York Thruway the posts continue from New York City — and there the figure is how far into the state the place is rather than the number on the sign. Distances are measured state by state, never across a gap.

5 current reports along the route, including 2 full closures. The 4 most serious are listed below. Always check with the responsible state DOT before setting off.

• Road closed

  Road construction on I-15-BL Both Directions from Commercial St to Willow Ln. All lanes closed. 9/14/2026 7:00 AM MT to…

  Road construction on I-15-BL Both Directions from Commercial St to Willow Ln. All lanes closed. 9/14/2026 7:00 AM MT to 1/8/2027 7:00 PM MT Mon, Tue, Wed, Thu, Fri, Sat, Sun: Active all day Width Restriction: 12ft Length Restriction: 50ft

  I-15-BL • eastbound • ID • Ongoing

• Lanes blocked

  I-15 mainline closure (lanes 1)

  Mainline closure. Work: Pavement Repair. Lanes closed: 1. Near Yermo, San Bernardino County.

  Yermo • North • CA • Until Oct 9, 11:59 AM

• Lanes blocked

  I-15 off ramp closure

  Off Ramp closure. Work: Paving Operation. Lanes closed: All. Near Rancho Cucamonga, San Bernardino County.

  Rancho Cucamonga • South • CA • Until Oct 13, 12:59 PM

• Lanes blocked

  I-15 on ramp closure

  On Ramp closure. Work: Paving Operation. Lanes closed: All. Near Ontario, San Bernardino County.

  Ontario • South • CA • Until Oct 15, 12:59 PM

Related Roads

I-15 Road Weather FAQ

Is I-15 closed right now?

Yes — 2 full closures are reported on I-15 as of Oct 9, 2026 3:17 AM UTC. 3 lane closures, roadworks or restrictions are in force. They are listed under closures and road blocks on this page.

What are I-15 road conditions today?

The map on this page colors the route along I-15 by what is on the pavement right now — dry, wet, slush, snow or ice — from radar and surface data, last updated Oct 9, 2026 3:00 AM UTC. Right now temperatures run from 50°F to 97°F and the strongest wind is 13 mph.

How long is Interstate 15, and which states does it cross?

I-15 runs 1,433 miles south to north, from San Diego, California to Sweet Grass, Montana, through 6 states: California, Nevada, Arizona, Utah, Idaho and Montana. The longest stretch is 401 miles across Utah. Mile markers restart at each state line, so Barstow is around mile 175 in California.

Are there mountain passes on I-15?

Yes — one on this site, Cajon Pass at 3,777 ft. It has its own summit page.

Are there live traffic cameras on I-15?

Yes. This page shows 6 live views on I-15 from the state transportation departments' own camera feeds, further down the page, refreshed each time you load it.

How often are I-15 road conditions updated?

The road surface and weather layers are rebuilt whenever this page is opened with data more than ten minutes old, and refreshed on a schedule in between, so nothing here is more than about two hours old even on a road nobody has looked at. Closures and road blocks are re-imported from the state 511 feeds every fifteen minutes, and the written state-by-state summaries are refreshed daily. Every section on this page carries the time its data was fetched.