The long run of rising apartment rents in Boston has hit a speed bump.

Boston one-bedroom and two-bedroom rents declined 0.3% in October, according to Apartment List. The slight drop-off ends a nine-month streak of rent increases, though Boston’s October rates remain 17.4% above last October’s numbers.

The current median one-bedroom apartment in Boston will set a renter back $2,039 per month, and $2,173 per month for a two-bedroom unit, according to Apartment List. The city doesn’t hold the fastest-growing nor most expensive rents in the region; the MetroWest suburb Waltham touts a year-over-year rent increase of 22.9%, while Brookline is costliest, with the median two-bedroom apartment monthly rent at $3,316.

The overall rent decline is part of a seasonal trend in which rents typically drop between October and February, Apartment List Senior Research Associate Rob Warnock said.

"It's just a reflection of when it’s convenient and financially prudent for people to move," he said. "Usually the summer is when prices go up the fastest because it’s convenient for people to move."

The Boston metro remains among the nation’s priciest regions for renters, driven in part by a housing shortage and an injection of new institutional investor landlords over the summer. Smaller multifamily properties are being scooped up by a wide variety of buyers, further straining affordability. The airtight single-family market also produced historic-high average prices, although it has since cooled.

Further apartment supply-and-demand relief may not come soon with a two-decade low delivery pipeline, according to Marcus & Millichap research. Multifamily permitting remains difficult in Boston and surrounding suburbs and construction challenges persist due to labor shortages and costly materials.

Rent control is a hot-button issue in Tuesday’s Boston mayoral race, with candidates City Councilor Michelle Wu backing the measure that was banned statewide in 1994, and City Councilor Annissa Essaibi George opposing rent stabilization.