FIRST THERE was the cold January. Then it turned abnormally warm in late winter. That was followed by a long cool spring, which is apparently why everyone's tomatoes are late. And now this.

Suspicion dawns that a screw has come loose in the great central thermostat governing Washington's climate. The subject is, of course, controversial. There are some who believe that we all made the mistake of complaining too much last January about the cold snap - and that the complaints were heard. But those of us who are experienced householders will think first of the screw that might have fallen out, or the wires that somehow got crossed in a fashion that the manufacturer will claim to have been impossible. As every householder also knows, the next hurdle is to try to find a reliable mechanic to repair it. At risk of diminishing the spirit of sunny optimism that customarily pervades this page, we have to tell you that, in our judgment, the thing isn't likely to be fixed soon.

There are adequate grounds for complaint in the behavior of Washington's weather even in a normal year. And even in the age of air conditioning, a siege like the present one becomes onerous. Yet there's a challenge here. This time, it's not just summe. It's a phenomenon of, possibly, historic proportions. If we survive ti, we can tell children yet unborn that we were there, in the great summer of 1977, when the very streets puckered and sagged under the sun. When the horizon itself vanished into a shimmering orange haze of smog and humidity. When the boa constrictors, the eyes reddened with pollution, vines beginning to take over the outer suburbs. A real summer, not like the kind (we'll say, looking back) that you get nowadays.

After all, Washington's summer is now on the verge of setting a couple of spectacular records. The all-time high score for the number of days in which the temperature reached 90 degrees is 59, set in 1966. This year we've already racked up 33 90-degree days, which means that there's almost an even chance of beating the 1966 mark. As for pollution, the alerts so far this year add up to 23 days. The record here, set in 1973, was 25 days, and when you consider the character of late August in this city, you would have to agree that we are certain to set a new high in bad air. That's a cheering thought, is it not? We aren't having merely a warm week or an uncomfortable summer. With a little luck, this could turn into the most miserable Washington summer in all of recorded history.