Gas prices have risen for 32 days straight, according to AAA.

That means that the average price for a gallon of regular unleaded gasoline has increased more than 13% over that period to $3.73.

It’s hitting wallets right in the middle of winter, when people are already looking at large home heating bills. And it comes just after many Americans have been hit with smaller paychecks, and are worried about looming budget cuts that could deliver an even deeper blow.

What’s behind the higher prices at the pump? It’s a confluence of factors, from rising crude oil prices, to production cuts and refinery closings.

“Right now, things are tight worldwide,” said Ray Carbone, president of New York commodities trading firm Paramount Options. “Refineries going down, unanticipated maintenance, and higher demand … going into driving season.”

Two-thirds of the cost of one gallon of gas comes from the price of crude, which has jumped 10% in the last two months, according to the Energy Information Administration. As the U.S. housing market experiences a resurgence, the jobs picture brightens and consumer spending expands, anticipation of higher oil demand is driving up prices. At the same time, fears have ebbed that there would be a protracted slowdown in China’s economy, which would have dampened global demand for oil.

OPEC, the powerful cartel of petroleum exporting countries, is also believed to have cut production by about 1 million barrels a day in the last few months, partly in response to rising oil production elsewhere, notably the United States.

Adding to that, several refineries are either preparing to, or have already, shut down for maintenance before their annual switch to summer gasoline, which is formulated differently.

For the average American, all this couldn’t be happening at a worse time.

Most of the country’s 160 million workers are taking home less pay each week since the payroll tax cuts expired last month.

(Source: CNN Money)