Portland OR, St George UT Earliest and latest travel Months?

March or October are doable, it depends on the year though. I have seen I15 closed in Farmington because of a lake effect storm in March.

Utah DOT has a good web page also, they have cameras and road conditions. They also have an AP you can install on your phone.

UDOT Traffic

Like others, we've driven this route perhaps 30 times, in every month of the year. Some January-March trips have been completely clear (and cold!), and I've also been in heavy snow in Eastern Oregon in October and late April.

I check the forecasts for Meacham OR, Baker City, and Snowville UT. Oregon's highway website is very good, and has cameras in all the critical spots. That's how I choose the actual day.

Thanks for the feedback! Much appreciated.

I will add that we stopped several times at the Wild Horse Casino. When the truckers left the truck stop down the road, we knew that the road was open and in good shape.

We have driven 84 in February about 10 times, seen snow a few times. But someone not on a schedule could easily travel even in February and avoid snow events. It's a main truck route, so cleared often and kept open all year. Just avoid traveling during or right after a winter storm. For the most part, not much to worry about.

I would not rule out anytime. Big item would be the Blue Mtns. in northeast Oregon. Watching weather and being flexible is key trip planning.