Washington — Detroit's veteran mayor, Coleman Young, was describing the temper in the big cities these days and, specifically, how blacks are responding to the high unemployment in his city.
''Unemployment is 20 percent in -Detroit,'' he told reporters over breakfast the other day. ''That means 40 percent unemployment among blacks - and more than 50 percent among teen-age blacks.''
''But,'' he went on, ''the city is still calm. There's no sign that, as some have predicted, we will have the racial explosion that we saw in the late 1960 s.''
''Instead,'' said Mr. Young, who, as president of the US Conference of Mayors , is in a good position to know what is happening in the nation's big cities, ''it's more like the Great Depression. Blacks see that every one is out of work, the whites as well as themselves. So they accept their situation as a condition of life - that you complain about it like you would complain about the rain.''
What Young was saying only confirmed current reports from other centers of urban discontent in the late 1960s that restlessness that might lead to uprisings just is not occurring - or about to occur.
Young said that things could break out ''spontaneously.'' But he thought not.
In addition, he said blacks have learned from their earlier experience that such uprisings only hurt themselves. ''They have learned,'' he said, ''that it is counterproductive to burn down your community and to burn and loot the stores where you are employed.''
''They have learned that you don't make your point by punishing yourself.''
He said that there is ''much resentment'' in Detroit about immigration - from Mexico, Puerto Rico, Southeast Asia, and elsewhere - among blacks unable to get work.
But, again, the mayor was talking about discontent, not about a possible racial clash.
One important reason for the relative calm, the mayor indicated, is that blacks while unhappy with the President do not see him as a racist.
They see his programs as helping the rich and hurting the poor and, therefore , as being racial in impact - since so many blacks are poor.
''But,'' Young said, ''The President isn't a racist. He really believes that what he is doing for the economy is in the best interests of everyone. . . . The problem,'' he said, ''is that Reagan is a barber when it comes to the economy - and what we need is a surgeon.''
The mayor himself takes sharp issue with the President. He would like Reagan to forget all about his New Federalism and get back to the longtime FDR approach of providing vast amounts of federal funds to pay for state and urban needs and services.
He said he thinks that transferring of federal responsibilities to the cities won't work simply because the taxpayers, at the lower level, will refuse to come up with the needed revenue.
Young, when moved to do so, can take strong action in the face of what he sees as injustice. Commissioned as an officer in the US Army during World War II , he had a brief stay in a Fort Knox stockade after he and scores of other Tuskegee airmen in the Air Corps shut down an officers' club that refused to serve black officers.
But it was on a pledge of restoring peace between the black community and the police of Detroit that Coleman Young was elected mayor in 1973. And in 1981 he was reelected to an unprecedented third four-year term.
Now Young, as leader of all the mayors, clearly is seeking to persuade the President - whom he considers a good man, a man of goodwill - to reshape his programs so as to give more hope - and justice - to the poor.
The mayor clearly is playing his peacekeeping role. And neither he nor those whom he represents are in any mood, at this point it seems, to use stronger means to show their displeasure.