STILL MORE RAIN. The central valve in the Washington Weathermat has evidently gotten stuck again. Last summer it was stuck on Hot. Now it's stuck on Wet. These repeated breakdowns in the celestial plumbing are a deplorate inconvenience to the public. Is there no sense of soceal responsibility to all those children who want to go out and play? And so sympathy for their parents, who have to put with them in the house? Think of all people out on street corners waiting for buses in the rush-hour downpours.

We have noted the shortcoming in the administration of the Washington Weathermat more than once. The system, we are sorry to say, has not proved very responsive. Complaining about the weather is like complaining about Congress. Rarely does it do much good, and frequently it makes things worse.

But there is no evidence, so far, that the current siege of rain is intended as a moral jugement on the recent conduct of the metropolitan area. On the contrary, we are confident that the trouble, on this occasion as on so many others, will turn out to be purely mechanical. This planet, after all, has been continuously inhabited for two billion years now, by one species or another, and you would have to agree that most of the previous tenants have contributed very little to the general maintenance and upkeep. Two billion years is a long time, and it stands to reason that some of the plumbung is showing its age. Probably the whole Weathermat system ought to be rebuilt, but as a practical matter it looks as though we are going to have to live with it for a while - the precise length of time depending mainly on how the nonproliferation issue goes.

Of course, there are worse things in this world than sticky valves in the weather machine. At least the Occoquan Reservoir is full again - although that thought does not bring much immediate comfort to those of us whose basements leak.