The Dow climbed 288 points, or 1.1%, on Monday. It was up 442 points earlier in the day.Investors were pleased that China and the United States reached a temporary trade truce. It's a big relief because the damaging trade war between the world's two largest economies was set to deepen in January. The Nasdaq soared 1.5%, while the S&P 500 jumped 1.1%."A truce is definitely better than an escalation of hostilities," Kit Juckes, strategist at Societe Generale, wrote to clients on Monday. Juckes said that even though investors may doubt the substance of the US-China agreement, "this morning's response reflects relief and a desire to pick up some last-ditch bargains."Not surprisingly, investors piled back into companies that rely on China for a significant chunk of their sales. That includes tech giants like Apple (AAPL), Nvidia (NVDA) and Qualcomm (QCOM) as well as industrial companies like Boeing (BA), Caterpillar (CAT) and Deere (DE). Tiffany (TIF) jumped 4%, while Wynn Resorts (WYNN) surged nearly 10%. "The market is thrilled to get a little bit of a reprieve," said Amanda Agati, co-chief investment strategist at PNC. "But it's early to say anything is done and to cross this worry off the list. There's still a long road ahead.The relief rally comes after the S&P 500 spiked nearly 5% last week, its best since December 2011. That rebound was triggered by hopes of progress on the trade front and a speech by Federal Reserve chief Jerome Powell that investors interpreted as a signal the central bank will not rush to raise interest rates."The China trade situation is the keystone in the arch of agita," said Sam Stovall, chief investment strategist at CFRA Research. The progress on talks with China means "now we have a very good chance of experiencing a Santa Claus rally," said Sam Stovall, chief investment strategist at CFRA Research.It wasn't just US markets celebrating. Major indexes in Hong Kong and Shanghai surged 2.5%. And markets in London, Frankfurt and Paris climbed 1% or more. Commodities also raced higher. Copper and soybeans climbed. US oil prices, boosted by hopes of an agreement by Russia and Saudi Arabia to cut output, surged 4%. After meeting on Saturday, US President Donald Trump and Chinese President Xi Jinping agreed to hold their fire on tariffs while they try to reach a trade deal. Trump agreed not to raise the 10% tariffs on $200 billion worth of Chinese goods for now. Those tariffs had been scheduled to automatically rise to 25% on January 1. And China said it would be willing to purchase a "very substantial" amount of agriculture, energy and other US products. Still, some analysts warned that the celebration on Wall Street could be short-lived. China and the United States now only have 90 days to sort out nagging trade issues that have been in contention for years, if not decades. And the statements that emerged from the trade meeting lacked concrete details."The beefiest part of Saturday evening's meeting between Presidents Trump and Xi may well have been the local sirloin served for dinner," Nicholas Colas, co-founder of DataTrek Research, wrote to clients on Monday.Goldman Sachs economists said the most likely outcomes are that the truce gets extended after 90 days or that the trade war escalates. The investment bank sees just a 20% chance over the next three months of a comprehensive deal rolling back tariffs."The specter of higher and broader US tariffs remains," Goldman Sachs chief US political economist Alec Phillips wrote to clients on Sunday.In any case, the progress on trade should allow investors to refocus on the fundamentals. But economic growth is expected to slow in 2019 because of the fading impact of the tax cuts, the impact of existing tariffs and higher borrowing costs. Analysts are calling for S&P 500 earnings growth to decelerate from about a blockbuster pace of 21% this year to 9% next year, according to FactSet.