I just called and here are the current road conditions into Yosemite. Remember, these can change at any time so you are REQUIRED to carry snow chains and should be able to put them on. You can be fined if you are not.
140 (from Mariposa)
R2 – Chains required into Yosemite. NO vehicles over 28ft through the Ferguson Slide area.
120 (from San Francisco, Groveland, etc.)
41 (from Fresno, Oakhurst, etc.)
R2 – Chains required into Yosemite from 3 miles north of Oakhurst.
Glacier Point Road (to Badger Pass)
R0 – Chains not required at this time.
As always, carry extra food, water, blankets and cold weather clothing in your car. Be sure to drive slow and use caution as Yosemite Roads are prone to black ice (140 can be especially bad along the river from Briceburg to Yosemite Valley.)