FOR A PERFECTLY good reason, California now has one of the shortest school years in a nation where time in school is woefully inadequate compared to other countries.

Concerned about teacher isolation that, among other results, sends many educators packing after their first year of teaching, California educators set aside so-called "in- service" or "staff development" time to train teachers and include them more in curricular and non-curricular school decisions.

The down side of this enlightened move was that the time given to teachers was taken from students' 180- day school year. California public school children now spend an average 176 days in school compared to an average 180 days nationwide.

Teachers need paid time outside the classroom. Children need more time in the classroom. One should not have to sacrifice for the other.

State Superintendent of Public Instruction Delaine Eastin has properly been pushing for a school year closer to 190 days, which still would not compare to more than 200 days in China, Korea, Taiwan, Japan, Germany and Israel.

In the meantime, the governor and Legislature included $50 million in this year's state budget to pay for one more day of schooling, rejecting a proposal to add more days.

Working on a schedule all their own, Sacramento politicians did not approve the money until after most California schools had already set their school-year calendars. But Capitol obtuseness should not penalize students. School leaders, including teachers' unions, should show that they are capable of flexibility driven by a recognition of what is best for the children. At the first opportunity, they should apply for the extra money and rejigger their calendars to add one more day of school in the 1997-98 year.

Schools that do not apply for the money that gives their students an extra day of learning have parents and the public to answer to.