FPUS55 KMSO 181823 ZFPMSO Zone Forecast Product National Weather Service Missoula MT 1223 PM MDT Mon May 18 2026 MTZ001-191000- Kootenai/Cabinet Region- Including the cities of Libby and Eureka 1223 PM MDT Mon May 18 2026 .TONIGHT...Partly cloudy early in the evening then becoming mostly cloudy. A 20 percent chance of rain early in the evening. Areas of frost and patchy fog late in the night. Lows in the 30s. .TUESDAY...Partly cloudy. Areas of frost in the morning. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the 60s to lower 70s. .TUESDAY NIGHT...Mostly cloudy with a 20 percent chance of rain in the evening, then partly cloudy after midnight. Lows in the mid 30s to lower 40s. .WEDNESDAY...Rain showers likely and a slight chance of thunderstorms in the afternoon. Chance of precipitation 70 percent. Highs in the 60s to lower 70s. .WEDNESDAY NIGHT...Mostly cloudy with a 40 percent chance of rain in the evening, then mostly clear after midnight. Lows in the mid 30s to lower 40s. .THURSDAY...Mostly sunny. Highs in the upper 60s to mid 70s. .THURSDAY NIGHT...Partly cloudy in the evening then becoming mostly cloudy. Lows in the upper 30s to mid 40s. .FRIDAY...Partly cloudy. Highs in the 70s. .FRIDAY NIGHT...Partly cloudy. Lows in the 40s. .SATURDAY...Partly cloudy. Highs in the 70s to lower 80s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s to lower 50s. .SUNDAY...Partly cloudy. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s to lower 50s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the upper 60s to mid 70s. $$ MTZ002-191000- West Glacier Region- Including the city of Swan Lake 1223 PM MDT Mon May 18 2026 .TONIGHT...Mostly cloudy. A 20 percent chance of rain and snow early in the evening. Areas of frost after midnight. Widespread frost late in the night. Lows in the upper 20s to mid 30s. .TUESDAY...Mostly cloudy. Areas of frost in the morning. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the 50s to lower 60s. Southwest winds to 15 mph. .TUESDAY NIGHT...Mostly cloudy with a 40 percent chance of rain. Lows in the mid 30s to lower 40s. Southwest winds to 15 mph. .WEDNESDAY...A chance of rain and snow in the morning, then rain showers likely and a slight chance of thunderstorms in the afternoon. Chance of precipitation 90 percent. Highs in the 50s. .WEDNESDAY NIGHT...Rain and snow likely in the evening, then partly cloudy with a chance of rain and snow after midnight. Chance of precipitation 70 percent. Lows in the 30s. .THURSDAY...Partly cloudy. Highs in the mid 50s to lower 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .FRIDAY...Partly cloudy. Highs in the 60s. .FRIDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SATURDAY...Partly cloudy. Highs in the 60s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Partly cloudy. Highs in the 60s. .SUNDAY NIGHT...Partly cloudy in the evening then becoming mostly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the upper 50s to mid 60s. $$ MTZ003-191000- Flathead/Mission Valleys- Including the cities of Kalispell, Polson, and St. Ignatius 1223 PM MDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT TUESDAY... .TONIGHT...Mostly cloudy then becoming partly cloudy after midnight then becoming mostly cloudy. A 20 percent chance of rain in the evening. Areas of frost late in the night. Lows in the 30s. .TUESDAY...Mostly cloudy. Areas of frost in the morning. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the 60s. .TUESDAY NIGHT...Mostly cloudy with a 20 percent chance of rain. Lows in the mid 30s to lower 40s. .WEDNESDAY...A chance of rain in the morning, then rain showers likely and a chance of thunderstorms in the afternoon. Chance of precipitation 80 percent. Highs in the upper 50s to mid 60s. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then partly cloudy after midnight. Chance of precipitation 60 percent. Lows in the mid 30s to lower 40s. .THURSDAY...Partly cloudy. Highs in the 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .FRIDAY...Partly cloudy. Highs in the mid 60s to lower 70s. .FRIDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SATURDAY...Partly cloudy. Highs in the 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s to lower 50s. .SUNDAY...Partly cloudy. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy in the evening then becoming mostly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of rain in the afternoon. Highs in the upper 60s to mid 70s. $$ MTZ004-191000- Lower Clark Fork Region- Including the cities of Noxon, Thompson Falls, and Superior 1223 PM MDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT TUESDAY... .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Areas of frost after midnight. Patchy fog late in the night. Lows in the upper 20s to mid 30s. .TUESDAY...Partly cloudy. Areas of frost in the morning. Highs in the upper 50s to mid 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .WEDNESDAY...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the upper 50s to mid 60s. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then partly cloudy with a slight chance of rain after midnight. Chance of precipitation 70 percent. Lows in the mid 30s to lower 40s. .THURSDAY...Partly cloudy. Highs in the 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .FRIDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .FRIDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SATURDAY...Partly cloudy. Highs in the 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Partly cloudy. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the mid 60s to lower 70s. $$ MTZ005-191000- Missoula/Bitterroot Valleys- Including the cities of Hamilton and Darby 1223 PM MDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT TUESDAY... .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Areas of frost after midnight. Widespread frost late in the night. Lows near 30. .TUESDAY...Partly cloudy. Widespread frost in the morning. Highs in the lower to mid 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the mid to upper 30s. .WEDNESDAY...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 40 percent. Highs in the lower to mid 60s. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then a chance of rain after midnight. Chance of precipitation 80 percent. Lows in the mid to upper 30s. .THURSDAY...Partly cloudy. Highs in the mid to upper 60s. .THURSDAY NIGHT...Partly cloudy. Lows near 40. .FRIDAY...Partly cloudy. Highs in the lower 70s. .FRIDAY NIGHT...Partly cloudy. Lows near 40. .SATURDAY...Partly cloudy. Highs in the mid to upper 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Partly cloudy. Highs in the mid to upper 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of rain in the afternoon. Highs in the lower to mid 70s. $$ MTZ006-191000- Bitterroot/Sapphire Mountains- Including the city of Sula 1223 PM MDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT TUESDAY... .TONIGHT...Partly cloudy. A 40 percent chance of areas of rain early in the evening. Widespread frost after midnight. Lows in the mid 20s to lower 30s. .TUESDAY...Partly cloudy. Widespread frost in the morning. Highs in the 50s to lower 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the 30s. .WEDNESDAY...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 40 percent. Highs in the mid 50s to lower 60s. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then rain and snow likely after midnight. Chance of precipitation 60 percent. Lows in the 30s. .THURSDAY...Partly cloudy. A 20 percent chance of rain and snow in the morning. Highs in the mid 50s to lower 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the 30s. .FRIDAY...Partly cloudy. Highs in the 60s. .FRIDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .SATURDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SUNDAY...Mostly sunny. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .MEMORIAL DAY...Partly cloudy. Slight chance of rain in the morning, then slight chance of showers and thunderstorms in the afternoon. Chance of precipitation 20 percent. Highs in the upper 60s to mid 70s. $$ MTZ007-191000- Butte/Blackfoot Region- Including the cities of Anaconda, Deer Lodge, and Drummond 1223 PM MDT Mon May 18 2026 .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Widespread frost after midnight. Lows in the mid 20s to lower 30s. .TUESDAY...Partly cloudy. Widespread frost in the morning. Highs in the mid 50s to lower 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the upper 20s to mid 30s. .WEDNESDAY...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 30 percent. Highs in the mid 50s to lower 60s. West winds to 15 mph. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then snow with rain likely after midnight. Chance of precipitation 90 percent. Lows in the 30s. Northwest winds to 15 mph. .THURSDAY...Partly cloudy. A 40 percent chance of rain and snow in the morning. Highs in the 50s to lower 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the 30s. .FRIDAY...Partly cloudy. Highs in the 60s. .FRIDAY NIGHT...Partly cloudy. Lows in the 30s to lower 40s. .SATURDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SUNDAY...Partly cloudy. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of showers and thunderstorms in the afternoon. Highs in the upper 60s to mid 70s. $$ MTZ043-191000- Potomac/Seeley Lake Region- Including the cities of East Missoula, Seeley Lake, and Clinton 1223 PM MDT Mon May 18 2026 .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Areas of frost after midnight. Widespread frost late in the night. Lows in the upper 20s to mid 30s. .TUESDAY...Partly cloudy. Widespread frost in the morning. A 20 percent chance of showers and thunderstorms in the afternoon. Highs in the mid 50s to lower 60s. .TUESDAY NIGHT...Mostly cloudy in the evening then clearing. Lows in the 30s. .WEDNESDAY...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the afternoon. Chance of precipitation 50 percent. Highs in the mid 50s to lower 60s. .WEDNESDAY NIGHT...Rain showers likely and a slight chance of thunderstorms in the evening, then a chance of rain after midnight. Chance of precipitation 80 percent. Lows in the 30s. .THURSDAY...Partly cloudy. Highs in the mid 50s to lower 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .FRIDAY...Partly cloudy. Highs in the 60s. .FRIDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SATURDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of rain in the afternoon. Highs in the mid 60s to lower 70s. $$ IDZ009-191000- Western Lemhi County- Including the city of Shoup 1223 PM MDT Mon May 18 2026 .TONIGHT...Partly cloudy. Lows in the upper 20s to mid 30s. .TUESDAY...Mostly sunny. Highs in the upper 50s to mid 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .WEDNESDAY...Mostly cloudy. Highs in the upper 50s to mid 60s. .WEDNESDAY NIGHT...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the evening, then a chance of rain after midnight. Chance of precipitation 40 percent. Lows in the mid 30s to lower 40s. Northwest winds to 15 mph. .THURSDAY...Partly cloudy. A 20 percent chance of rain and snow in the morning. Highs in the upper 50s to mid 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .FRIDAY...Partly cloudy. Highs in the mid 60s to lower 70s. .FRIDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SATURDAY...Mostly sunny. Highs in the upper 60s to mid 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Mostly sunny. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s to lower 50s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of showers and thunderstorms in the afternoon. Highs in the upper 60s to mid 70s. $$ IDZ010-191000- Eastern Lemhi County- Including the cities of Salmon and Leadore 1223 PM MDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT TUESDAY... .TONIGHT...Partly cloudy. Widespread frost late in the night. Lows in the 20s to lower 30s. .TUESDAY...Partly cloudy. Highs in the mid 50s to lower 60s. .TUESDAY NIGHT...Mostly cloudy in the evening then becoming partly cloudy. Lows in the 30s. .WEDNESDAY...Mostly cloudy. Highs in the upper 50s to mid 60s. .WEDNESDAY NIGHT...Mostly cloudy. Chance of rain showers and a slight chance of thunderstorms in the evening, then a chance of rain after midnight. Chance of precipitation 50 percent. Lows in the 30s. Northwest winds to 15 mph. .THURSDAY...Partly cloudy. A 20 percent chance of rain and snow in the morning. Highs in the upper 50s to mid 60s. .THURSDAY NIGHT...Partly cloudy. Lows in the 30s. .FRIDAY...Partly cloudy. Highs in the mid 60s to lower 70s. .FRIDAY NIGHT...Partly cloudy. Lows in the mid 30s to lower 40s. .SATURDAY...Partly cloudy. Highs in the upper 60s to mid 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the 40s. .SUNDAY...Mostly sunny. Highs in the 70s to lower 80s. .SUNDAY NIGHT...Partly cloudy. Lows in the 40s. .MEMORIAL DAY...Partly cloudy. A 20 percent chance of showers and thunderstorms in the afternoon. Highs in the 70s. $$ IDZ005-191000- Northern Clearwater Mountains- Including the cities of Pierce and Elk River 1123 AM PDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT TUESDAY... .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Patchy fog after midnight. Patchy frost after midnight, then areas of frost late in the night. Lows in the upper 20s to mid 30s. .TUESDAY...Partly cloudy. Areas of frost and patchy fog in the morning. Highs in the 60s. .TUESDAY NIGHT...Partly cloudy. Lows in the 30s to lower 40s. .WEDNESDAY...Mostly cloudy. Highs in the 60s. .WEDNESDAY NIGHT...Mostly cloudy with a 30 percent chance of rain in the evening, then mostly clear after midnight. Lows in the 30s. .THURSDAY...Mostly sunny. Highs in the mid 60s to lower 70s. .THURSDAY NIGHT...Partly cloudy in the evening then becoming mostly cloudy. Lows in the mid 30s to lower 40s. .FRIDAY...Mostly sunny. Highs in the upper 60s to mid 70s. .FRIDAY NIGHT...Mostly clear. Lows in the mid 30s to lower 40s. .SATURDAY...Partly cloudy. Highs in the 70s. .SATURDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .SUNDAY...Partly cloudy. Highs in the 70s. .SUNDAY NIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the mid 60s to lower 70s. $$ IDZ006-191000- Southern Clearwater Mountains- Including the cities of Powell, Elk City, and Dixie 1123 AM PDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 8 AM PDT TUESDAY... .TONIGHT...Partly cloudy. A 20 percent chance of rain early in the evening. Widespread frost and areas of fog after midnight. Lows 25 to 40. .TUESDAY...Partly cloudy. Widespread frost and areas of fog in the morning. Highs 52 to 66. .TUESDAY NIGHT...Partly cloudy. Lows 31 to 46. .WEDNESDAY...Mostly cloudy. Highs 53 to 66. .WEDNESDAY NIGHT...Mostly cloudy with a chance of rain showers and a slight chance of thunderstorms in the evening, then partly cloudy with a chance of rain after midnight. Chance of precipitation 40 percent. Lows 31 to 45. Northwest winds to 15 mph. .THURSDAY...Mostly sunny. Highs 55 to 70. .THURSDAY NIGHT...Partly cloudy. Lows 32 to 47. .FRIDAY...Mostly sunny. Highs 61 to 76. .FRIDAY NIGHT...Mostly clear. Lows 34 to 49. .SATURDAY...Partly cloudy. Highs 67 to 81. .SATURDAY NIGHT...Partly cloudy. Lows 36 to 51. .SUNDAY...Partly cloudy. Highs 67 to 81. .SUNDAY NIGHT...Partly cloudy. Lows 35 to 50. .MEMORIAL DAY...Partly cloudy. Slight chance of rain in the morning, then slight chance of showers and thunderstorms in the afternoon. Chance of precipitation 20 percent. Highs in the 60s to lower 70s. $$ IDZ007-191000- Orofino/Grangeville Region- Including the city of Kooskia 1123 AM PDT Mon May 18 2026 ...FROST ADVISORY IN EFFECT FROM 11 PM THIS EVENING TO 9 AM PDT TUESDAY... .TONIGHT...Mostly clear. Lows in the mid 30s to lower 40s. .TUESDAY...Partly cloudy. Highs in the 60s to lower 70s. .TUESDAY NIGHT...Partly cloudy in the evening then becoming mostly cloudy. Lows in the upper 30s to mid 40s. .WEDNESDAY...Partly cloudy. Highs in the 60s to lower 70s. .WEDNESDAY NIGHT...Partly cloudy with a 30 percent chance of rain. Lows in the upper 30s to mid 40s. Northwest winds to 15 mph. .THURSDAY...Mostly sunny. Highs in the 60s to mid 70s. .THURSDAY NIGHT...Partly cloudy. Lows in the 40s. .FRIDAY...Mostly sunny. Highs in the 70s. .FRIDAY NIGHT...Mostly clear. Lows in the 40s. .SATURDAY...Mostly sunny. Highs in the 70s to lower 80s. .SATURDAY NIGHT...Partly cloudy. Lows in the mid 40s to lower 50s. .SUNDAY...Mostly sunny. Highs in the 70s to lower 80s. .SUNDAY NIGHT...Partly cloudy. Lows in the mid 40s to lower 50s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the mid 60s to lower 70s. $$ IDZ008-191000- Lower Hells Canyon/Salmon River Region- Including the cities of Riggins and White Bird 1123 AM PDT Mon May 18 2026 .TONIGHT...Partly cloudy. Lows in the upper 30s to mid 40s. North winds to 15 mph in the evening. .TUESDAY...Mostly sunny. Highs in the 60s to lower 70s. .TUESDAY NIGHT...Partly cloudy. Lows in the 40s. .WEDNESDAY...Partly cloudy. Highs in the lower 60s to mid 70s. North winds to 15 mph. .WEDNESDAY NIGHT...Partly cloudy. Lows in the 40s. Northeast winds to 15 mph. .THURSDAY...Mostly sunny. Highs 63 to 76. .THURSDAY NIGHT...Partly cloudy. Lows in the mid 40s to lower 50s. .FRIDAY...Mostly sunny. Highs in the upper 60s to lower 80s. .FRIDAY NIGHT...Mostly clear. Lows in the mid 40s to lower 50s. .SATURDAY...Mostly sunny. Highs in the 70s to lower 80s. .SATURDAY NIGHT...Partly cloudy. Lows in the upper 40s to mid 50s. .SUNDAY...Mostly sunny. Highs in the mid 70s to lower 80s. .SUNDAY NIGHT...Partly cloudy. Lows in the upper 40s to mid 50s. .MEMORIAL DAY...Partly cloudy with a 20 percent chance of rain. Highs in the mid 60s to lower 70s. $$