BOSTON – Commuter rail on-time reliability dropped in October to its lowest monthly rate in at least a year, transportation officials said Monday, putting some of the blame on two storms with high winds that downed trees.

Trains across the system arrived within five minutes of the scheduled time at a rate of 84.6 percent in October and within 10 minutes of schedule at a rate of 91.9 percent, according to figures presented to the T and Department of Transportation boards.

Both numbers were the lowest since at least October 2018.

Every single line’s five-minute performance dropped in varying degrees from September, but the worst performance was on the Franklin Line, where 79.2 percent of trains ran within five minutes of the schedule.

Storms on Oct. 17 and Oct. 31, which knocked out power and downed trees in parts of the state, “caused 36 percent of all delay,” according to the presentation.

An MBTA spokesperson did not respond to requests for comment on whether that figure represented all delays in October or for the year.

Between December 2018 and May 2019, the commuter rail system saw its best six-month span of on-time performance since at least July 2014, when Keolis began its contract to operate the network.