
https://www.ncsl.org/resources/details/legislative-session-length
That’s pretty standard for state legislatures. A lot of states treat the legislature as a part-time job and expect their elected representatives to have other responsibilities as well. It used to even be common for states to only convene every other year.
The biggest issue is water, and it would be difficult for them if they lose access to the Colorado River. Currently, only 10% of the river’s flow reaches Mexico, so it’s not unreasonable to believe that California would be in trouble if they don’t secure control of the upper basin. In any case, it would make for a complicated legal battle between an independent California, the United States, and Mexico.