It looked like everyone was going to talk about the weather but nobody was going to pay for it.

Now it is clear that somebody will pay for it, but nobody knows whether it will be the Department of Transportation or the Department of Commerce. In these days of harsh budget problems, the question of who's going to pay for what has become central, and many departments are looking to see if somebody else can pick up part of the tab.

The weather report is the latest chapter in the saga of the Reagan administration's attempt to have users of federal services pay for them.

The weather in question is aviation weather: information about weather conditions that would affect flight. Because this information is used by pilots, the Office of Management and Budget reasoned that aviators, not the general taxpayer, should pay the cost of providing it.

Thus the big tax bill now before Congress authorizes new revenues for the airport and airways trust fund which would be used to pay for the air traffic control system and for, it turns out, the collection of aviation weather information. Users will pay for these services, primarily through taxes on tickets and fuel.

The OMB figures it will cost Commerce's National Weather Service $26.7 million in fiscal 1983 to give DOT's Federal Aviation Administration all the weather information (including forecasts, temperatures and wind conditions both at ground level and aloft) that the FAA's air traffic controllers pass on to pilots. The trust fund authorization permits transferring that amount from DOT to Commerce. Historically, aviation weather collection has been funded in the Commerce budget.

However, the trust fund, like the rest of the bill, has not been approved by the full Congress. If it is, there will be two potential sources of funds for aviation weather and an unresolved argument.

First the argument. Many FAA employes take weather readings, particularly at more remote airports that don't have any weather service employes. Those FAA readings are transmitted to the nearest National Weather Service office and become part of the forecasting process.

Administrator J. Lynn Helms was asked by the House Appropriations subcommitte on transportation recently if it were possible that the weather service would owe the FAA money. "I believe that may be the case," Helms said.

Regardless of what Helms believes, OMB provides no credit for the FAA temperature-takers in calculating the $26.7 million.

When that money for Commerce reached the transportation subcommittee, it was removed. There was, after all, no authorization for trust fund revenues in the first place, no offset for FAA's contribution to the system, and besides, Commerce has always paid for the weather service.

The Appropriations subcommittee in charge of the Commerce Department put the money in the Commerce appropriations bill, now awaiting House action, thus assuring that there will be aviation weather. If the tax bill passes, the differences will have to be ironed out, probably in a House-Senate conference.