Earliest date to travel through Rockies snow-free

November 19, 2018 12:59 PM

We'd like to drive from Toronto to LA and back as early as reasonably possible next year. To LA through Canada and back to Toronto via Arizona (Grand Canyon), Utah, Colorado, Nebraska, etc. But we don't want to die on a lonely Colorado mountain in a snow storm. What's the earliest time of year we could reasonably expect to be snow-free on each of these routes?

I know there are always freaky, weird, unexpected storms. I'm just trying to learn the averages, so to speak. Outside of these semi-catastrophic early spring storms, are the US interstate highways through the mountains well plowed in the winter? What about in Canada?
Thanks.

posted by feelinggood to Travel & Transportation (9 answers total)

Mid-June.
posted by JamesBay at 12:59 PM on November 19, 2018

Yep, mid-June. I used to drive Chicago-LA four times a year, and routinely faced nontrivial snowstorms in May on that route (I-80-76-70-15). With that said, I only ever had a problem on the interstate (I-70) once -- they do a pretty good job keeping it plowed IME. Anything smaller than an interstate though and you can forget about it.

If your route is flexible at all: When I drove in the winter (December or January), and also at other times if I'd looked ahead and seen that the weather would be bad, I took the southern route instead -- I-40 to I-44 through Albuquerque and Oklahoma City, and then getting on I-55 in St. Louis. Not as scenic, but definitely safer/easier in bad weather.
posted by goodbyewaffles at 1:11 PM on November 19, 2018

are the US interstate highways through the mountains well plowed in the winter?

The interstate highways are often the only roads plowed during smaller snowstorms. If you don't want to wait until June, and do feel comfortable driving on plowed highways, but not driving through active snowfall, consider adding a day or two of potential travel time so that you can stop and wait out a storm.

COtrip will let you know about road conditions, plow locations, and any chaining requirements for the Colorado portion of the drive, complete with cameras.
posted by asperity at 1:12 PM on November 19, 2018

I've driven Colorado highways in the dead of winter. Except during and immediately after an actual snow event, the roads are well-groomed. Colorado does *not* fuck around clearing highways. (mostly because so much of their tax base is tourism - rich people who want to ski fresh powder!)

In fact, as long as you don't try it in a storm, US 550 is terrifyingly picturesque in snow.

(See this for an article on clearing that road...)

If you absolutely cannot drive in snow, "July" is the answer. I was out there with my dad two years ago at the end of June and drove through 6+ inches that the locals didn't even blink at.
posted by notsnot at 1:13 PM on November 19, 2018

Here is some info on what weather condidtions to expect for Rogers Pass, where the Trans Canada highway crosses the Continental Divide.

https://www.pc.gc.ca/en/pn-np/bc/glacier/visit/meteo-weather
posted by TORunner at 1:23 PM on November 19, 2018

Are you planning to drive to Vancouver and then head down the coast? The high passes in Alberta and BC can potentially see snow into early June. If you do have flexibility to deal with a potential brief delay for the odd late-season storm, you can reasonably expect to make the outbound leg in late May.
posted by theory at 1:47 PM on November 19, 2018

If you're in Toronto, surely you appreciate that there is a gulf between "no snow whatsoever" and "impassible to traffic; please die alone of hypothermia".

Weatherspark does a very good job of summarizing climate data in understandable terms and will be a useful resource, although note that there can be a big gap between what is experienced at lower and higher elevations, and not all high elevation locations will have data. For instance, on the Trans-Canada has a station at the AB/BC border (where you will note there is literally no day in the year where snow has not fallen) but not one at the Roger's Pass, which is slightly higher and gets more snow. Freak snowstorms can happen in May and June; any earlier and they're common enough they're not really freak snowstorms anymore.

If you're interested in going as early as possible, you can probably go a few weeks earlier by going out through the US and back through Canada, since winter is generally longer up here.
posted by Homeboy Trouble at 2:34 PM on November 19, 2018

Also, if you want a fairly high degree of certainty there won't be snow, the timeframe may make sense for you to go out through the US and return through Canada in that you could avoid holiday traffic by going through the US on the Victoria Day weekend, then returning through Canada over the Memorial Day weekend.
posted by Homeboy Trouble at 2:38 PM on November 19, 2018

Thank you to everyone. Just the kind of stuff I was looking for.
:-)
posted by feelinggood at 10:48 AM on November 29, 2018