When was the last time it snowed in Burbank CA?

There are some that will laugh and say "never" but, that is highly unlikely.

There was a pretty decent storm that rolled over Orange County that left a blanket of 3" to 6" of snow all across the county in 1949.

This piece from the OC Register doesn't mention Fullerton explicitly but, I'd say it is highly likely in Jan 1949.