The trip is aimed at highlighting his push to combat global warming and strengthen infrastructure, while helping fellow Democrat Gavin Newsom try to hold on to California's governorship.
Biden visited the National Interagency Fire Center in Boise, a hub designed to coordinate resources on wildfires - and held a briefing with state and local officials before flying to Sacramento, California, to see wildfire damage in the area.
The president said fire season in the United States is starting earlier each year and that this year alone, 44,000 wildfires in the country had consumed 5.4 million acres (2.2 million hectares) - an area roughly the size of New Jersey.
"Thank God, thank God we have you," Biden told firefighters in the room." He pledged to help federal firefighters make at least $15 an hour and said he is committed to raising the pay gap for firefighters who protect federal wildlands.
"The reality is we have a global warming problem, a serious global warming problem," Biden said, pegging the economic damage from extreme weather events last year at $99 billion.
Last week, he called climate change an existential threat during a trip to New Jersey and New York. https://reut.rs/2YSfqi2
White House principal deputy press secretary Karine Jean-Pierre said on Monday that one in three Americans is affected by the increasing frequency of extreme weather events and that Biden's message on his first trip to the U.S. West Coast as president would be that the "climate crisis is in code red."
The White House said late on Sunday that Biden had approved U.S disaster funding to help California amid the Caldor Fire, which has been burning since mid-August in the Sierra Nevada range. He ordered other federal assistance earlier this month after declaring the situation an emergency.
Biden will head later to Long Beach, California, to take part in an event with Newsom, an ally who is fighting to survive a Republican-led recall. Biden's presence, the day before polls close, is meant to help mobilize Democrats to vote and secure Democratic leadership of the nation's most-populous state.
Democrats outnumber Republicans in California and recent polling shows a majority of likely voters opposing the recall, but Biden and Newsom are not taking anything for granted.
Vice President Kamala Harris, a former U.S. senator from California, campaigned for Newsom last week and painted the recall, which is backed financially by state and national Republican groups, as part of a broader Republican effort to expand conservative restrictions on voting, abortion and LGBTQ rights.
On Tuesday, Biden will turn his focus to infrastructure during a stop in Denver where he will tout multitrillion-dollar legislation he is seeking to repair U.S. roads and bridges along with a swath of other domestic policy priorities.
One of the bills faces roadblocks within his own party. U.S. Senator Joe Manchin said on Sunday that lawmakers were unlikely to pass a $3.5 trillion budget package supported by Democrats by a Sept. 27 deadline, but added he could support a smaller $1 trillion-$1.5 trillion bill. Manchin's backing is critical as Democrats need all of their members in the evenly split Senate to support the spending measure.
During a trip on Saturday to commemorate the 20th anniversary of the Sept. 11 attacks, Biden expressed optimism that the bills would pass.
"I think we're going to get major pieces of legislation through, both on a bipartisan basis," he told reporters in Shanksville, Pennsylvania.
(Reporting by Steve Holland in Boise, Idaho and Jeff Mason and Nandita Bose in Washington; Editing by Steve Orlofsky and Peter Cooney)