JUNE IS the month of, among other things, weddings, graduations, first trips to the beach - and a less celebrated recurrence with a lot less to recommend it: social promotion. That is the insidious educational practice of promoting to the next grade students whose performance and achivements plainly do not qualify them to move on. Generally, they are students who either received failing grades or were simply given passing marks for work they actually failed or never did at all. No one knows how many of the city's public school students get social promotions every year. The evidence of it - poor performance on standardized tests, among other things - doesn't show up until later. But there's little doubt that it's used widely.

The efforts of school officials to install a new curriculum that involves a great deal of testing is an acknowledgement that this is so. And the practice isn't limited to Washington's schools, or urban schools. It exists in schools across the land. The alarm over its consequences - high school graduates who read and write poorly, if at all - has helped produce increasing demands for tougher academic standards and for minimum-competency tests.

Social promotion isn't a new phenomenon. Rather it's almost as old as the public schools. It resulted from the belief that making some pupils repeat a grade would do them more harm than good. Until recently, it was used relatively sparingly.But within the last decade, particularly in urban schools, it seems to have become more prevalent because teachers and administrators find it a convenient mechanism for ridding themselves of troublesome or difficult-to-teach students. There are undoubtedly some situations in which extraordinary circumstances justify the promotion of a student who has actually failed the grade. When social promotion is practiced indiscriminately, however, it diminishes the incentives for both teachers and students to work.

There are several things school officials can do to limit the use of this dubious practice and to address the needs of students who must repeat a grade. First, they should make it clear that passing marks are a prerequisite for promotion. And they should enforce that policy through the use of various kinds of tests that will tell school officials and the public which stuudents, schools and teachers aren't performing satisfactorily. The competence testing in the new curriculum that District school officials are preparing should accomplish this purpose, if it is used properly. Second, school officials should develop an effective program to help students who must repeat a grade. This could include such things as revising the grade curriculum as much as possible to present the same material to the students in a different way, and grouping retained students in their own class, apart from those students entering the grade for the first time. Finally, school officials should develop a program for those mentally retarded students who aren't likely to ever meet the promotion standards, but who can learn basic skills. These programs need not involve great additional expenditures of school funds. What they do require is imaginative thinking and a commitment by school officials to educating the students they are responsible for.