Omaha to San Diego for Christmas

Most likely the worst weather will in the first day, regardless of which directly you drive.

One year I returned from Chicago to Seattle after Christmas - via bus. The shortest route via Mpls was closed due to storms in the Dakotas. So we passed through Omaha to SLC. It was a cold and windy during a lunch stop at Cheyenne, but no snow. In fact we didn't see significant snow until we crossed the Washington mountains.

In other words, a storm could be blowing across Wyoming, or it could be hitting the Denver and points south. I40 around Flagstaff is also known for winter closings. So if you are flexible, and weather looks go to the west, I'd go straight out I80 and then I15 south.

Since you are going and returning, you take both routes around the Colorado mountains. No need to restrict yourself, especially if timing is flexible.

Get south as soon as you can and head for SD. We're going to Parker AZ for Christmas via Hwy 70 and I 10 from Roswell NM. We'll be in San Diego the Monday after Christmas going I 10, then south to I 8 over the mountains.

Too soon to tell what the weather will be. An ice storm can come out of nowhere and move its way across AZ, NM, TX and screw up travel like it did for us a few years ago.

Taking I-8 into San Diego is a steep climb over the mountains to the east. I-8 might be less congested than I-10. I-40 is usually windy and is known for some terrible weather but coming from Neb you should be used to that, lol.