Once again, clocks around the country were shifted an hour this weekend to accommodate daylight saving time. And once again, Metro seemed to have a problem keeping up.

Clocks were pushed forward early Sunday, disrupting sleep patterns and leaving the nation’s microwaves an hour behind. The lost hour also meant a costlier commute for some Metro riders Monday morning when peak fares, which are supposed to go until 9:30 a.m., were charged until 10:30 a.m.

It’s unclear how many riders paid extra and whether the problem affected only specific stations or the entire system, Metro spokeswoman Caroline Lukas said.

Lukas said she didn’t know what caused the additional hour of peak fares, and she wouldn’t speculate on whether the problems stemmed from the change to daylight saving time.

She said all affected riders would have the additional fare refunded to their cards upon the next entry to the transit system, Lukas said.

However, one Metro rider who was affected by the extra charge in the morning said the refund had not been applied by the evening.

For riders who have been told to expect fare increases every other year, the difference between peak and off-peak fares can be substantial. Someone who commutes between Vienna and King Street or between Shady Grove and L’Enfant Plaza can save nearly $5 a day by avoiding both peak periods.

A trip from Vienna to King Street costs $5.75 during the peak and $3.50 off-peak.

Hans Bader of Arlington County times his commute on the Orange Line so that he can avoid peak fares. He enters the East Falls Church station after 9:30 a.m., and he heads to the Farragut West station after 7 p.m. But during his commute on Monday morning, he noticed he was overcharged.

“It’s very frustrating,” said Bader, 43, a lawyer. “You try and economize, and you end up paying the full fare anyway even though you attempted to time your commute to minimize the cost to your family.”

Bader said a station manager at Farragut West told him that the higher charge may have stemmed from pressing the card against the turnstile more than once. But Bader later spoke with his boss, who also entered the system after 9:30 a.m. and was similarly charged the peak amount.

This is the second consecutive time Metro has had an issue when the clocks have changed.

In November, Metro was supposed to stay open an extra hour as clocks turned back, but the system shut down early. Riders counting on Metro to get home were stranded.

The transit agency apologized for the early shutdown but did not offer an explanation at the time. An e-mail from Metro General Manager Richard Sarles to members of Metro’s board shortly after that incident cited poor internal communications following “a long week” preparing for Hurricane Sandy, which hit the East Coast the week before the time change.

His e-mail and others were obtained through a public records request filed by The Washington Post shortly after the November incident.

For many riders, the trip Monday morning was aggravated by major delays and severe crowding on the Blue and Yellow lines.

A piece of equipment leaked fluid on a stretch of the tracks near Reagan National Airport, leading to single-tracking between Pentagon City and Braddock Road for the duration of the morning rush.

Riders wedged themselves onto packed platforms and trains for trips that some said took twice as long as normal, with some reporting commutes lasting more than two hours. The platform at Pentagon City was so jammed that the line stretched up the escalators and almost reached the fare gates.

Trains resumed normal two-track service about 10:30 a.m. Monday.