Sun Day for President Carter in Colorado turned out to mean chill showers and political storms.

The president sought to dispel the gloom by announcing at the site of the Solar Energy Research Institute in nearby Golden that he has found an additional $100 million in this year's budget for research on solar and other renewable-source energy.

But his announcement - designed to quiet criticism of an earlier cutback in solar research funds from the level of last year's Ford administration budget - did not ease the tension as Carter began a three-day swing through the politically hostile West.

A chill rain was falling as the president, wearing no raincoat, arrived in Denver, along with Cabinet members James R. Schlesinger, Cecil D. Andrus and Bob Bergland.

Waiting for him at the foot of the ramp was Sen. Flod K. Haskell (D-Colo.), who had complained publicly on Tuesday that Andrus, the interior secretary, and Bergland, the agriculture secretary, were "the symbols of the two most hated Carter administration policies in the West."

Haskell's comment embarrassed other Democrats, but few of them were prepared to dispute his judgment. Colorado Gov. Richard Lamm, a Democrat who like Haskell is a candidate for reelection this year, said, "I've been avoiding the subject all week. I don't want to be a poor host. Just say the West, like the President, believes in the power of redemption."

As the motorcade left Denver for South Table Mountain, future site of the solar research laboratory that Colorado won in 1976 in stiff competition with other states, White House press secretary Jody Powell leaned out from his car and said:

"It it's still raining when we get to the top of the mountain, Sen. Haskell is going to announce that the solar lab is being shifted to Massachusetts."

But the warning did not work. It was raining so hard on the mountain that Carter was forced to cut short his speech.

Yesterday's stop was the first on a three-day trip that will also take Carter to California, Oregon and Washington. He lost all four states in 1976, and Polls have shown his political support even weaker today, in part because of his water and agriculture policies. Lamm said, "This whole region is just neurotic on the subject of the Carter administration."

In his speech, Carter depicted his administration as a strong supporter of solar energy, but that is not the reputation it enjoys among congressional advocates of sun power.

"His overall record is not good," said Rep. Timothy E. Wirth (D-Colo.), whose district hosts the solar lab. "Despite the president's stated commitment to this program, it has not been reflected in the Department of Energy budget. They cut the budget by $10 million in the House Science Comittee."

In March, 44 representatives and 26 senators, comprising a "solar coalition," wrote Carter to say they were "disappointed that the federal government is doing less than it could do in a reasonable, well-planned and thorough program to stimulate the use of solar energy."

Carter sought to answer those criticisms with his visit here, yesterday.

In his speech here, Carter cited a recent study by the Council on Environmental Quality which estimated that solar energy could meet one-quarter of the United States' energy by the 2000 and perhaps more than half by 2020.

"Progress toward goals is a cornerstone of this nation's energy policy," he said.

Carter said he had ordered Secretary of Energy James R. Schlesinger to begin a Cabinet-level review of solar policy, with a report due by September that would be the basis for next year's budget decisions and legislative recommendations.

He said the energy Department's goal is to make solar energy competitive in price with conventional energy by 1990.

"The question is no longer whether solar energy works," Carter said. "We know it works. The only question is how to cut costs so that solar power can be used more widely."

He said the Energy Department's year-old energy proposal, a billion dollar's worth of tax credits for solar installations would be available to homeowners.

he president said he planned to spend $100 million over the next three years to install solar heating in federal buildings, adding, "I intend to have a demonstration solar hot water heating system installed at the White House."

He also announced that the Farmers Home Administration will loan $14 million to Lamar, Colo., to convert feedlot waste into methane gas in an experiement designed to meet 40 percent of that city's power needs.