The Russian ruble is rebounding — but can this last?

The ruble, it appears, is going from zero to hero. The Washington Post reports.

Russia’s currency went from being one of the worst-performing in the world last year to the best-performing in the first few months of 2015, according to Bloomberg. And few analysts saw the turnaround coming.

The ruble was hovering at about 55 to the dollar this week — still a far cry from the 35-to-the-dollar exchange rate it was trading at a year ago but significantly stronger than it had been over the winter.

But the question is, why?

Economists had predicted that the ruble would continue to perform poorly as the price of oil stayed low, because Russia’s economy is largely dependent on oil revenue. But oil prices are still low, and the ruble has slowly but steadily grown stronger against the dollar.

The Russian economy also was expected to contract, but it grew 0.4 percent in the last three months of 2014. It’s a small movement, but in the right direction.

Such numbers do not mean, of course, that the economic fate of the average Russian has improved. Most have seen their buying power diminished, as consumer prices rose over the past year to keep up with the falling ruble, but ruble-denominated salaries did not.

It is also far from clear whether the trend will continue. Over the last year, the ruble’s exchange rate has been dramatically affected not just by the falling price of oil, but also by changes to the interest rate, the state of the conflict in eastern Ukraine, and the various rounds of sanctions imposed on Russia since it moved to annex Crimea.

But going forward, the appetite for sanctions appears to be changing, at least in the European Union. Alexis Tsipras, the new Greek prime minister, who visits Moscow on Wednesday, has declared himself to be against further Russian sanctions — and it will take a unanimous vote in the summer to continue E.U. sanctions against Russia.

And although the situation in eastern Ukraine is far from peaceful, there have been no large-scale flare-ups along the front line for several weeks.

Meanwhile, Elvira Nabiullina, governor of Russia’s central bank, said Tuesday that she expects inflation to fall quickly, provided there are no surprises, and that the central bank would continue cutting interest rates this year.