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7-Day Outlook: August 28–September 3, 2026

A progressive late-summer pattern will bring two rounds of unsettled weather to the Saint John Valley through Sunday, separated by a cooler and drier Saturday. After a relatively mild start to the day, with temperatures in the middle 60s across northern Maine, an upper-level trough and associated cold front will cross the region, supporting scattered showers and thunderstorms, some of which may become strong with gusty winds and small hail. Showers will become more numerous during the afternoon, with thunderstorms most likely from mid-afternoon into early evening. Skies will remain mostly cloudy, with highs reaching the mid to upper 70s. South winds of 5 to 10 mph will shift to the west as the front passes. Most locations will receive less than 0.10 inch of rain, although locally higher amounts are possible with thunderstorms.

Showers and thunderstorms will diminish quickly this evening as the front moves east. Cooler and drier air will spread into the Valley overnight as west winds continue around 5 mph. Clouds will gradually clear, with temperatures falling into the mid to upper 40s by Saturday morning.

Saturday will provide the best weather of the weekend as surface high pressure builds toward northern New England. Patchy early morning valley fog will give way to sunny skies, lower humidity, and seasonably cool temperatures in the lower 70s. Light west winds early will increase to 5 to 10 mph during the day. Mostly clear skies will continue Saturday night, with temperatures falling into the upper 40s to lower 50s. Patchy valley fog may redevelop toward daybreak Sunday.

The dry weather will be short-lived as another upper-level disturbance approaches from Canada on Sunday. After any early fog dissipates, skies will become partly sunny with temperatures reaching the upper 60s to lower 70s. Increasing southwest winds of 5 to 10 mph may gust around 20 mph ahead of the approaching system. Showers will become possible by midday, with scattered thunderstorms developing during the afternoon and showers becoming more likely toward late afternoon. Rainfall will generally remain light, although locally higher amounts will again be possible with thunderstorms.

Showers and thunderstorms should diminish Sunday evening as another front crosses the region. Winds will shift northwest around 5 mph, with partial clearing overnight. Temperatures will fall into the mid to upper 40s, and patchy valley fog may develop again toward Monday morning.

A fairly quiet start to the week will give way to a more unsettled pattern across the Saint John Valley by midweek. Behind Sunday’s cold front, cooler and drier northwest flow will settle across northern Maine Monday as the upper-level trough moves east and surface high pressure builds into the region. Patchy valley fog may develop early Monday morning before giving way to sunny skies. Temperatures will reach the upper 60s to lower 70s, with northwest winds of 5 to 10 mph and occasional gusts around 20 mph. Skies will become partly cloudy Monday night as temperatures fall into the mid to upper 40s.

High pressure will remain influential Tuesday, providing another dry and pleasant day with abundant sunshine and temperatures reaching the lower to mid-70s. As the high gradually shifts away, the low-level flow will begin to turn east to southeast ahead of an increasingly active pattern. Clouds will begin to increase Tuesday night, with a slight chance of showers developing late. Overnight temperatures will fall into the upper 40s to around 50.

By Wednesday, northern New England will lie near the cooler side of a frontal zone extending across the region. Disturbances moving through strengthening west-to-northwest flow aloft may interact with this boundary, bringing increasing clouds and periods of showers to northern Maine. Wednesday will be partly sunny to mostly cloudy, with a 50 percent chance of showers and highs in the upper 60s to lower 70s. Showers may continue Wednesday night beneath mostly cloudy skies, with temperatures falling into the lower 50s.

Unsettled conditions are expected to persist Thursday as additional disturbances move through the region. Mostly cloudy skies and scattered showers are expected, with highs generally in the upper 60s to around 70. The chance of showers will continue Thursday night as temperatures fall into the upper 40s to lower 50s.

The precise timing and track of individual disturbances remain uncertain, so precipitation coverage and amounts will become clearer as the period approaches. Overall, Monday and Tuesday offer the best opportunity for dry weather, followed by a cloudier and more unsettled Wednesday and Thursday.

Outlooks updated 7-9 AM weekdays & 8-10 AM weekends and holidays. Long-range outlooks indicate broader temperature and precipitation trends rather than precise day-to-day forecasts.

Updated every 3-6 hours from NWS Caribou

Weather Notice: This information is based on available computer models and data and may not reflect current conditions or later forecast updates. Always visit NWS Caribou at https://www.weather.gov/car/ for the latest official watches, warnings, and advisories for northern Maine.

Credits

• Sun/Moon data from US Naval Observatory with additional information from timeanddate.com.
• NOAA Warning Banner provided by WillyWeather.com.
• Until Dec. 2026, additional Archived Weather Data from Apex Wx is at the University of Utah's MesoWest
• Apex Wx Weather Data at Synoptic Data (successor to MesoWest)
  
• Apex Wx logo by Joanna Becker ©2016 (Visit Bushi and Brush Arts Dojo)

How accurate are forecasts? On average, for the first 72 hours the accuracy is 90 percent. For days 4-7 it is 70 percent. After seven days, it is 50 percent—just good for indicating trends. On social media and other similar sites, posts that show a forecast model run a week out are just for clicks and likes, and are not considered reliable. Extended forecasts are subject to change as weather patterns evolve so should be considered guidance rather than precise predictions. Check for updated forecasts and advisories as conditions develop.