* C$ at C$0.9969 to US$, or $1.0031 * Weak Canadian building data weighs on currency * Investors seen paring back on riskier assets ahead of vote * Pending Greek austerity vote weighs on euro, global tone By Alastair Sharp TORONTO, Nov 5 (Reuters) - The Canadian dollar weakened on Monday as data showed construction activity looked set to drop and investors limited exposure to riskier assets ahead of Tuesday's U.S. presidential election. The currency hit a session low after the value of Canadian building permits unexpectedly fell sharply in September, data from Statistics Canada showed. Separately, Canada's federal housing agency said new homebuilding is expected to moderate further in the final quarter of 2012. The resource-linked currency had already been trading weaker, following the cautious tone in a raft of commodities, as investors pared back bets on riskier assets before Americans go to the polls on Tuesday in a vote with global ramifications. At 10:12 a.m. (1512 GMT) the Canadian dollar was trading at C$0.9969 to the greenback, or $1.0031, compared with C$0.9956, or $1.0044, at Friday's North American close. "The move in the Canadian dollar is consistent with the move in most of the currencies that trade as risk proxies," said Adam Cole, global head of foreign exchange strategy at Royal Bank of Canada. "It may be the uncertainty of the U.S. election as one factor." The presidential vote will be closely watched by financial markets. The future makeup of the U.S. Congress will also play a role in how the country deals with the so-called fiscal cliff - looming spending cuts and tax hikes that could push the world's largest economy into recession. Gold and oil were steady, while copper hit a two-month low. RBC's Cole said that worries about a Greek vote on Wednesday over austerity measures was keeping the euro under pressure and adding to the more cautious overall tone. The Canadian currency strengthened to its highest level in almost three weeks against the euro. It also firmed against the British pound and the Swiss franc . The price of Canadian government debt rose across the curve, with the two-year bond up 2 Canadian cents to yield 1.059 percent, while the benchmark 10-year bond rose 21 Canadian cents to yield 1.747 percent.