Northwest Montana

Issued: 10/19/2026 8:05 p.m. MDT

Tonight...Fair skies this evening then increasing high cloudiness overnight. Lows in the mid 20s to mid 30s except lower 40s in thermal belts on slopes and hillsides with near 40 around 5000 feet. Light wind.

Monday…Considerable high clouds and mild. Highs in the upper 50s to mid 60s with mid 50s around 5000 feet. Light wind.

Monday night…Considerable high clouds and mild. Lows in the 30s except mid 40s in thermal belts on slopes and hillsides with lower 40s around 5000 feet. Light wind.

Tuesday...Variable high cloudiness in the morning then becoming mostly sunny in the afternoon. Highs in the 60s to near 70 with mid 50s around 5000 feet. Light wind.

Extended Outlook(Wednesday through Sunday):

Wednesday...Dry and unseasonably warm. Lows in the upper 20s to upper 30s except upper 40s in thermal belts on slopes and hillsides with mid 40s around 5000 feet. Highs in the 60s to near 70 with mid 50s around 5000 feet.

Thursday and Friday...Cooler with a chance of rain and high mountain snow. Lows in the 30s. Highs in the 50s. Around 5000 feet lows in the lower 40s Thursday cooling to lower 30s Friday. Highs in the mid 40s Thursday cooling to the mid 30s Friday.

Saturday...Dry except for a slight chance of valley rain showers and mountain snow showers late in the day along the Idaho border. Lows in the lower 20s to lower 30s with upper 20s around 5000 feet. Highs in the mid 40s to lower 50s with mid 30s around 5000 feet.

Sunday...Cool and locally breezy with a chance of valley rain and snow and mountain snow. Lows in the upper 20s to mid 30s with upper 20s around 5000 feet. Highs in the mid 40s to lower 50s with near 30 around 5000 feet.

In-Depth Weather Discussion for Northwest Montana/North Idaho/Northern Rockies 

Issued 10/12/2026 7:45 p.m. MDT / 6:45 p.m. PDT

SHORT TERM (MONDAY NIGHT THROUGH WEDNESDAY):       

     After a chilly, unsettled, and in some locations especially across the Purcell Trench in North Idaho very windy second half of the weekend along with all of our mountains seeing their first accumulating snow of the season things have settled down as the surface high responsible for the gusty northeast winds and upslope light snow showers on Sunday in Northwest Montana has shifted further south. This has allowed clear skies and light winds to prevail and will be setting our region up for the coldest night of the season since last March at least across valley locations. Thermal belts on slopes, hillsides and across higher elevations saw their coldest night Sunday night into early Monday morning. Many of our colder Northwest Montana valleys will see temperatures drop into the teens with all other valley locations away from the immediate shorelines of Pend Oreille Lake seeing temperatures well down into the 20s. Pend Oreille Lake's water temperature in hovering in the mid 50s and this will tend to keep areas right along the shoreline near 209 to 30 degrees, still cold just not as cold as areas even a quarter of a mile or more inland. Many lakes and rivers will likely see steam fog develop for a couple of hours either side of sunrise with the cold temperatures and relatively warm water sources and the contrast of the two promoting shallow, localized instability. Can't rule out some patchy freezing fog and low clouds each night and morning especially around Priest Lake and the Kootenai Valley near Libby either as these areas are often the first to develop fog and low clouds under a stable atmosphere. Temperatures will be near seasonal averages on Tuesday before rising a few degrees above average by Wednesday. Will also perhaps see a light southwest breeze pick up Wednesday afternoon with a weak shortwave passage but whether those light breezes surface outside of the highest ridge tops appears unlikely.                                      

LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY): 

     Our next weather maker is already spinning out in the West Pacific as what is now typhoon Koguma is currently sitting well of the coast of Japan and really is not being steered in any direction at the moment. Models appear to be slowly drifting Koguma slowly to the northwest and eventually to the north but unlike it's predecessor Choi-Wan which constructively phased with an upper level trough pushing off the coast of Japan and produced our recent cold and rainy/snowy weather Koguma is expected to destructively phase with the westerlies by around Thursday or possibly even Friday. This will result in the flattening out of the North Pacific jet with models showing a strong east to west zonal North Pacific jet strengthening by next weekend and beginning to plow multiple shortwaves into the Northwest and Northern Rockies. The first one looks to move through around Saturday and exits by early Sunday. This will likely produce only some clouds and increased west to southwesterly breezes. The next system which will be the surface low and associated upper level trough from what was Koguma by this time will move in by Monday bringing more winds from the southwest along with much better chances for valley rain and snow. This time the precipitation will tend to favor North Idaho and those areas of Northwest Montana west of the Cabinet Mountains which is often the case with systems pushing in off the Pacific. A bit too early to say how much precipitation will fall but it looks overall wetter than this weekend's system at least for North Idaho. Further systems are lined up in the zonal jet to follow next week so more typical October-like weather may finally be arriving in the Northern Rockies.