How late in the year can I travel US 50 through Colorado and make it to Utah before I have to head south? I am considering a time frame of Oct through December? I know there is no way to know for sure but wonder what other late trips you have experience in the two states? My thought is to take off and once I find weather bad head south!!!

This website is probably the best weather forecast for traveling available: http://oss.weathershare.org/?Center=42.18529516716987,-122.097248046875&Zoom=8&Layers=CCTV,traffic 

There are many traffic/weather cameras throughout CO to see what lies ahead.

Edited August 18 by Ray,IN

You'd have Monarch Pass to cross at 11,300' elevation.  October might be o.k. because snow would probably melt fast but iffy beyond that.

I agree, my only concern would be getting west of Monarch Pass by early Nov. On avg by mid Nov the daily highs up there are below freezing (32F) and begin the permanent snow cover until April. Of course in the Co high country above 10,000 it can snow any month of the year, but those are usually short and melted the next day.  Once you get over Monarch Pass its all downhill and much milder weather even into Dec. If a storm approaches in the western slope, you have lots of options to stop for a night while it blows through. 

Then you have to choose a route into Utah,  US50 turns into I-70 around Grand Junction. If you want to stay off the interstate there are 2 or 3 options, but you could be headed back up to 8000 ft elevation, not good in Dec.

Edited August 19 by JRP

  On 8/19/2019 at 2:10 AM, JRP said:

I agree, my only concern would be getting west of Monarch Pass by early Nov. On avg by mid Nov the daily highs up there are below freezing (32F) and begin the permanent snow cover until April. Of course in the Co high country above 10,000 it can snow any month of the year, but those are usually short and melted the next day.  Once you get over Monarch Pass its all downhill and much milder weather even into Dec. If a storm approaches in the western slope, you have lots of options to stop for a night while it blows through. 

Then you have to choose a route into Utah,  US50 turns into I-70 around Grand Junction. If you want to stay off the interstate there are 2 or 3 options, but you could be headed back up to 8000 ft elevation, not good in Dec.

Thank you!

We came over Monarch in mid September one year.  Feet of Snow on the ground at the summit  and snow banks on both sides of the pass.   Yes, it had been plowed but the roadway was wet from the melting snow off the snow banks.   Following week (end of September) snow storm hit Colorado Springs - just a skiff, but told us winter was coming.

I wouldn't drive it in October, but that is just us.   We'd be taking I-80 across or even better, dropping down to I-40 (Ballon Festival!).  And by November we are on I-10.   We didn't retire to have to worry about snow. 

2/3rd's of the way through August, and both DriveBC and Yukon Highways were advising against travel, going as far as closing the AlCan for a bit. Snow in mountain passes can happen at almost anytime of the year. Watch the forecast, keep your tanks topped up, and have provisions needed for overnight on board.

We have always had terrible weather at Red Mountain, is that Monarch Pass? Including snow and sleet in June and July. And I don't mean snow sprinkles, this was the heavy wet snow. No telling what it's like in November.

Once you are in Utah you should be fine tho not immune to snow. In fact I'd much rather do Zion and Arches in cool weather than summer. They are both hotter than Hades and I think you can drive in the Zion Valley.

I just saw a forecast showing storms already stacking up in the Pacific off WA and OR so an early winter may be at hand. Or maybe not who knows. The weather guy said it looked more like January than August tho.

  On 8/21/2019 at 9:44 AM, agesilaus said:

We have always had terrible weather at Red Mountain, is that Monarch Pass? Including snow and sleet in June and July. And I don't mean snow sprinkles, this was the heavy wet snow. No telling what it's like in November.

Are you thinking of Red Mountain like at Ouray/Silverton, CO?  Not the same as Monarch.

delete 

Edited August 22 by noteven

OP asked about fall travel not spring

  On 8/21/2019 at 9:44 AM, agesilaus said:

We have always had terrible weather at Red Mountain, is that Monarch Pass?

Red Mountain Pass is on US-550 and Monarch is US-50. 

All Colorado year round passes are well maintained in the winter but, as a Colorado resident, I would hesitate to take my RV over one of the high passes unless I knew for sure the road conditions. Even Raton Pass which is a "low" pass can be a little unnerving in the winter. This is the best place to look at Colorado road conditions.