Straphangers are spending more time waiting on subway platforms or in stalled trains, according to the latest MTA figures.

About 25 percent of all weekday trains and half of all weekend trains are late, the data show — and the delays have been getting longer.

In August, the worst weekday offenders were the G train, which was on time only 17 percent of the time, and the Q and 1 trains, both of which saw skyrocketing delays compared to August 2008.

“I have a couple of horror stories [about several lines],” subway and bus chief Howard Roberts admitted yesterday.

He was referring to a slew of repair-related schedule changes that recently hit the G train and to the August ceiling collapse at the 181st Street station in Manhattan that continues to plague the No. 1 train.

On weekends last August, the E, F and R trains ranked the worst –with each line delayed more than 90 percent of the time.