Verdon Gorge, possible in March? Road conditons

No problem really, the elevation is relatively low and it very rarely snows. Just be aware that the roads are very twisty, and the southern rim road ("corniche sublime") is on the narrow side - still worth it though.
Even ice on the trails should no longer be a major risk by March, depending on the weather when you go.

In February 2019, my husband and I drove to Verdon Gorge twice in a two-week period from Aix-en-Provence. It was lovely and the weather was as well. That may have been a fluke, however. If conditions are good, please take a picnic lunch to enjoy outside the car at one of the parking spots and enjoy the "gorge"ous views. The glacial melt is spectacular. There was virtually no one else there.
Just Google "Verdon Gorge weather". This is what came up today--wish I were there right now!
https://weather.com/weather/tenday/l/Sainte+Croix+du+Verdon+Alpes+de+Haute+Provence+France?canonicalCityId=aefd4b486f8ea27eb63b291997a04b38d5f4508c5b72f7a9ce49961dba15f6e9

It wasn't a fluke. It's exactly as Lindy and balso have described it.

Thank you!

A few years ago we spent 3 days at the Auberge du Point Sublime, in Rougon. This was in September, no problem with ice or snow. The gorge is spectacular, and the village of Moustière is also well worth a visit. But be extra cautious on the roads in the gorge. In many spots, they narrow to one lane, with lots of blind curves, no guard rails, and sheer drop-offs. At night, they are really treacherous, since there are often no painted stripes to mark the edges of the pavement. In fact, after dark, there were almost no cars passing our hotel.

Heed the warning above; the roads are not easy if you are not used to mountain driving.
Staying in Moustiers-Sainte-Marie will remove the need for nighttime driving, as there are plenty of restaurants in the village. It will be livelier than the places in the gorge (La Palud, Point Sublime, Rougon), yet only a short drive away.
Aiguines is also an option, but access is less easy.