The month of May has arrived, but a cold front is on its way, according to weather officials.

An “out of season” cold front is expected to approach the Hawaiian isles today, leading to an unstable southerly flow that will produce scattered showers, some briefly heavy, according to the National Weather Service.

The front, about 275 miles northwest of Kauai as of about 9:45 a.m. today, is expected to move down the island chain late tonight into early Sunday. A period of heavy rainfall, gusty winds, and possibly thunderstorms is expected to move down most of the island chain on Saturday.

Starting Saturday night into early next week, drier and cooler northwest winds will fill in behind the front. Trades are unlikely to make a return until Thursday.

A high wind watch, meanwhile, has been issued for Big Island summits. Westerly winds are expected to strengthen across the high summits of the Big Island tonight, weather officials said, and will likely exceed warning levels of 60 miles per hour by Saturday morning.

The winds are expected to increase tonight and continue through the weekend, making travel to the summits difficult or dangerous.