Since 2001, Halloween in Buffalo has only been precipitation-free four times.
National Weather Service forecasts show that pattern is holding.
Halloween revelers, and the parents who trot along with them, will require waterproof costumes or umbrellas to stay dry as forecasts show rain is expected across the Buffalo Niagara region most of Wednesday.
Some of the warmest air in weeks is forecast in Buffalo Wednesday bolstered by a southerly flow of air ahead of an approaching cold front. Daytime temperatures in the upper 50s, to near 60 degrees, are expected.
"These mild readings will last through the evening," the weather service said. "Rain shower coverage will increase through the day Wednesday."
It added: "Confidence continues to increase that the Wednesday night through Thursday night time frame will feature an extended period of wet weather as the frontal zone stalls over the region."
The average temperatures on Halloween in Buffalo are a high of 54 degrees and a low of 38 degrees.
Last year, there was one-tenth inch of snow. That was the first measurable snow on Halloween in Buffalo since 1993.
In the meantime, expect mostly sunny and seasonable conditions in Buffalo Tuesday. A daytime high of 53 degrees is forecast.
There's a 40 percent chance of showers developing overnight Tuesday night with temperatures dipping into the mid- to upper 40s.