A known and strongly negative correlation exists between the US dollar to the Canadian dollar (USD/CAD) currency pair and the price of oil; when oil weakens so does USD/CAD price rises. because CAD main exporting oil to 80% US. By the way. Here is my explain with more detail,
Crude oil is Canada’s largest component of exported goods hence CAD weakens as oil prices fall. In addition, the price of crude oil is denominated in USD therefore the USD/CAD correlation is intensified. Due to this strong correlation many investors find ways to trade oil through trading USD/CAD.