Blackfoot, ID → Phoenix, AZ

Your 674-mile journey from Blackfoot, Idaho to Phoenix, Arizona follows a dramatic arc southward through some of the West's most transformative landscapes. From Blackfoot, you'll head south on Interstate 15, a major corridor that serves as your primary route for the majority of this drive. The highway carries you through southeastern Idaho's high plains before descending into Utah, where you'll pass near the edges of the Great Salt Lake and continue through Salt Lake City's metropolitan area. Beyond Salt Lake, I-15 remains your faithful companion as it cuts through increasingly arid terrain, eventually carrying you across the Nevada-Arizona border and into the Sonoran Desert landscape that characterizes the approach to Phoenix.

The terrain you'll encounter shifts dramatically as you travel south, beginning with Idaho's agricultural valleys and transitioning into Utah's high elevation plateaus around 4,500 to 5,000 feet. As you descend toward Arizona, the elevation gradually decreases and the landscape becomes increasingly desert-like, with sagebrush giving way to creosote bushes and distinctive saguaro cacti as you near Phoenix. You'll witness the Wasatch Mountains as you approach Salt Lake City, and later glimpse the Oquirrh Range and other Utah ranges before entering the more open, expansive desert valleys of southern Nevada and Arizona.

Notable cities punctuating your drive include Salt Lake City, roughly 300 miles into your journey, where you might grab fuel and food while passing through Utah's capital. Further south, you'll skirt past St. George, Utah, a charming gateway town near some of the region's most famous parks, before continuing into the Arizona Strip and onward to Phoenix. The drive itself is remarkably straightforward, with I-15 handling most of the distance, though you should prepare for elevation changes—particularly around Salt Lake City—and occasional construction zones that can slow progress.

Spring and fall offer the most pleasant driving conditions for this route, with moderate temperatures and excellent visibility. Summer heat, particularly in southern Nevada and Arizona, can create challenging driving conditions with temperatures exceeding 100 degrees Fahrenheit, while winter snow in Utah's higher elevations can occasionally complicate the northern portions of your drive.

The 674-mile drive from Blackfoot, Idaho to Phoenix, Arizona takes approximately 13h 28m under normal conditions. Weather along this route can vary significantly, especially through mountainous terrain where elevation changes can bring sudden weather shifts. Route Outlook helps you find the safest time to travel by showing you weather conditions at every point along your route, timed to when you'll actually be there.

Common Weather Hazards on This Route

• Winter storms and heavy snowfall (November through April)
• Black ice on mountain passes and bridges
• Extreme heat and dust storms in desert regions
• Flash floods during monsoon season (July through September)

Seasonal Driving Considerations

Mountain passes along this corridor can be treacherous from October through May, with chain requirements, road closures, and whiteout conditions at higher elevations. Summer brings its own challenges — afternoon thunderstorms are common above 7,000 feet, and construction season narrows lanes on key highways. Always check pass conditions before departing, and carry emergency supplies during the colder months.

Best Time to Drive Blackfoot to Phoenix

For long drives like this 674-mile journey, planning is essential. Consider breaking the trip into segments if weather looks challenging. The best approach is to check conditions for multiple departure times using Route Outlook's optimizer, which considers weather at each point when you'll actually be there.

Driving Strategy

Covering 674 miles from Blackfoot to Phoenix is a full-day or multi-day drive that requires advance planning. Break the route into manageable segments, planning fuel and rest stops every 2-3 hours. Weather that looks fine at departure may deteriorate significantly at the midpoint. Consider booking overnight accommodation if the forecast shows deteriorating conditions in the latter half. Route Outlook's segment-level weather data helps you identify exactly where and when conditions will change.

Frequently Asked Questions