By Fergal Smith

Jan 31 (Reuters) - The Canadian dollar weakened against its U.S. counterpart on Friday in volatile trading as investors weighed the uncertain makeup and timing of expected U.S. tariffs on goods from Canada and Mexico.

The loonie CAD= was trading 0.2% lower at 1.4520 per U.S. dollar, or 68.87 U.S. cents, after moving in a range of 1.4374 to 1.4550. For the week, the currency was on track to lose 1.2%. It touched on Thursday its weakest level in nearly five years at 1.4592.

U.S. President Donald Trump is expected to announce new tariffs on imports from Canada and Mexico that would become effective on March 1, but would include a process for the countries to seek specific exemptions for certain imports, three people familiar with the planning told Reuters.

White House spokeswoman Karoline Leavitt said a Feb.1 deadline still holds.

"Operationally, it's really difficult to see how they would implement a 25% tariff by (Saturday)," said Bipan Rai, head of ETF and structured solutions strategy at BMO Global Asset Management, adding that a delayed implementation could reduce some of the premium that has been built into USD-CAD due to trade uncertainty.

"It does feel that there is a significant chunk of the market that is long dollar-Canada and the degree of sensitivity is very high right now," Rai said.

The Bank of Canada on Wednesday said that most of the loonie's decline in recent months was due to rising uncertainty around trade policies as it cut its benchmark interest rate by 25 basis points to 3% to support the economy. The loonie has weakened about 6% since the beginning of October.

Canadian gross domestic product declined by 0.2% in November, weighed by work stoppages in inland transportation and at ports. Preliminary estimates showed GDP rebounding by 0.2% in December and annualized fourth-quarter growth of 1.8%.

The Canadian 10-year yield CA10YT=RR was down 3 basis points at 3.092%, after earlier touching its lowest level since Dec. 11 at 3.062%.

(Reporting by Fergal Smith; Editing by Will Dunham)

((fergal.smith@thomsonreuters.com; +1 647 480 7446))