BOZEMAN — A stormy start to the week will bring rounds of thunderstorms and periods of rain to southwest Montana, including Butte, Bozeman, Dillon, and surrounding valleys. Conditions improve steadily by midweek, with warmer and drier weather returning before another possible weather-maker arrives next weekend.
SUNDAY NIGHT
Thunderstorms will remain possible through the evening across southwest Montana as a strengthening storm system approaches from the Pacific Northwest. Some storms may become strong, with heavy downpours, hail up to around one inch in diameter, and wind gusts approaching 50 mph. Areas that see repeated storms could experience localized flooding concerns, especially near burn scars and poor-drainage locations. A second round of showers and thunderstorms is expected to develop overnight and continue into Monday morning.
MONDAY
Periods of rain and scattered thunderstorms continue across Butte, Bozeman, Dillon, and the surrounding region. Southwest Montana is expected to receive less rainfall than areas farther north and west, but occasional moderate rain and embedded thunderstorms will still make for a cool and unsettled day. Mountain areas will remain cloudy and damp, with reduced visibility at times.
MONDAY NIGHT
Showers continue through the evening and overnight as the storm system slowly moves through the Northern Rockies. While the heaviest rainfall remains focused across northwest Montana, southwest Montana can expect lingering rain and isolated thunderstorms capable of producing brief heavy downpours and frequent lightning.
TUESDAY
The storm begins pulling away, leading to decreasing precipitation across southwest Montana. Scattered showers may linger through the day, especially near the mountains, but improving conditions are expected by afternoon and evening. Temperatures remain cooler than normal for early September.
WEDNESDAY
A drying trend takes hold across the region. Morning fog and low clouds may develop in valleys around Butte and Dillon due to lingering ground moisture, but increasing sunshine during the afternoon will help temperatures recover.
THURSDAY
Pleasant weather returns with a mix of sunshine and scattered clouds. Morning valley fog remains possible in some locations, but most of southwest Montana will enjoy dry conditions with temperatures climbing back toward seasonal averages.
FRIDAY
One of the nicest days of the week is expected. Butte, Bozeman, and Dillon should see mild afternoon temperatures, abundant sunshine, and generally dry conditions. Highs will continue to rebound into the comfortable late-summer range.
SATURDAY
Forecast confidence decreases, but long-range guidance points toward another weather system approaching the Northern Rockies. There is roughly a 70 percent chance of renewed unsettled weather developing during the weekend. Cooler temperatures and increasing shower chances may return, particularly over the mountains.
SUNDAY
The active pattern may continue into the latter half of the weekend. Depending on the strength of the incoming system, southwest Montana could see another round of showers, cooler temperatures, and potentially early-season snow on the highest peaks above 7,000 feet along the Continental Divide. Forecast details should become clearer as the week progresses.
