The Dunes can be really cold, but dry if there's not a weather system in the area. Moving west toward Durango on Hwy 160 you will go through Wolf Creek pass, which is high and often clogged with snow during a storm. The good thing about the area however, is the reliability of weather forecasts. You can see storms coming a day or two ahead, allowing you to shift locations to avoid them or to catch them for better photos.
Alternate destinations: At Cortez (west of Durango on Hwy 160), turn north on Hwy 666 and drive to Montecello, Utah. Half an hour north from there on HWY 163 to the Needles District of Canyonlands NP and Newspaper Rock, or one hour to Moab and Arches NP, Deadhorse Point State Park, Island in the Sky district of Canyonlands, and a whole lot more without names.
A half hour south of Monticello on Hwy 163 is Blanding UT with access on Hwy 95 to Natural Bridges National Monument, Glenn Canyon National Recreation Area, and with a left at Hanksville on Hwy 24 you get to Capitol Reef NP. Just beyond Capitol Reef turn south on Hwy 12 at Teasdale to reach Escalante, Kodachrome Basin and Bryce Canyon NP. Just west of Bryce you can go south on Hwy 89 to Coral Sand Dunes State Park, Kanab and ultimately Grand Canyon, or veer west on state hwy 15 at Mount Carmel Junction to reach familiar ground in Zion NP, Saint George, Valley of Fire and Las Vegas. I've made the drive from Moab to Zion in a day via this route many times, but it's a long day and the road between Teasdale and Escalante gets quite high at one point, bringing up issues of snow and road conditions in the wake of storms.
As an alternative to all that, after leaving Cortez on HWY 666 you could veer north on Hwy 141 to Natarita, where you intercept the dramatic Dolores River canyon, then on to Grand Junction via Gateway (more drama). At Grand Junction go west on I-70 a very few miles to reach Colorado National Monument, then continue west on I-70 to Crescent Junction with the Book Cliffs to your right (north) all along the way. At Crescent Junction you could turn south on Hwy 163 to intercept the previous route via Moab or continue west over the San Rafael Swell to eventually intercept I-15 and a direct route south to Zion and Vegas, 6-7 hours from Crescent Junction. You could also veer south from I-70 on Hwy 24 to Hanksville and reconnect there- my usual choice.
That's a "tip of the iceberg" tour, with lots more detail along any of those routes and choices based upon your available time and the kind of vehicle you are driving. I spend 5 months a year in that area, and would be happy to help you refine your choices. Contact me via email.