Apex Wx

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Sun. Aug. 30 – Tue. Sep. 1
A progressive northern-stream pattern will bring a cold front across northern Maine Sunday afternoon, followed by high pressure building into the region from western Quebec Sunday night and Monday. Ahead of the front, scattered showers and isolated thunderstorms will develop as daytime heating combines with the approaching boundary. Instability will be limited, but stronger winds aloft could allow an isolated storm to produce gusty winds and a brief heavier downpour. Cooler and drier air will spread into the Saint John Valley behind the front Sunday night, followed by mostly sunny and seasonably cool weather Monday. High pressure will gradually shift east Tuesday as the next weather system begins organizing, but its influence should keep northern Maine mainly dry through the day. Clouds will begin increasing later Tuesday and Tuesday night ahead of a more unsettled period beginning Wednesday.

Sunday: After a sunny start with a waning moon in the western sky over the Valley this morning, a cold front north of the Saint Lawrence will move through the region this afternoon, bringing a chance of showers and isolated thunderstorms. Morning sunshine will increasingly give way to clouds, with showers developing around the Saint John Valley during the afternoon. An isolated thunderstorm is possible and could briefly produce gusty winds and a heavier downpour, but widespread severe weather is not expected. Highs should reach around 70–72°F before cooler air begins arriving as high pressure moves in behind the departing front. West to southwest winds around 5–10 mph may become gusty before shifting northwest behind the front. Showers should taper during the evening, with overnight lows falling into the mid- to upper 40s.

Monday: High pressure building into the Valley from western Quebec brings the best weather of the period. Expect abundant sunshine, low humidity, and seasonably cool conditions with highs near 70°F. Northwest winds around 5–10 mph will gradually diminish. Mostly clear skies and increasingly light winds Monday night should allow temperatures to fall into the upper 40s, with patchy late-night river-valley fog possible.

Tuesday: High pressure will gradually move east as the next weather system approaches the region. Any early valley fog should dissipate quickly, followed by partly to mostly sunny skies. The departing high should keep Fort Kent largely insulated from precipitation developing farther south. Winds will be light, with afternoon temperatures again around 70–72°F. Clouds may begin increasing later Tuesday or Tuesday night as the larger midweek system approaches. Overnight lows will fall into the upper 40s to around 50°F, with light east winds expected.

Wed. Sep. 2 – Sat. Sep. 5
Quiet weather early in the week will give way to a more unsettled pattern Wednesday into Thursday as low pressure moves through eastern Canada and an associated upper-level trough approaches northern New England. A secondary area of low pressure may also develop near the Gulf of Maine or farther offshore, helping spread additional moisture northward into the region. The exact track and timing of this system remain somewhat uncertain, but the heaviest rainfall currently appears more likely across southern and Downeast Maine, with lighter amounts expected farther north.

Wednesday: The day will begin partly sunny across the Saint John Valley, with clouds increasing as the system approaches. A few showers may develop during the afternoon, although much of the day should remain dry. Temperatures will reach the upper 60s to around 70, with southeast winds of 5 to 10 mph. Showers will become more likely Wednesday night as skies turn mostly cloudy. Overnight temperatures will fall into the upper 40s to low 50s.

Thursday: Mostly cloudy and unsettled conditions are expected with periods of showers possible throughout the day. Temperatures will remain seasonably cool, with highs in the mid to upper 60s. Showers may continue Thursday night under mostly cloudy skies, with lows around 50°F.

Friday: The system will gradually moves east, but lingering moisture and the nearby upper-level trough will maintain mostly cloudy skies and a chance of showers. Highs will again reach the mid to upper 60s, followed by overnight lows in the upper 40s to around 50. Additional showers may occur Friday night.

Saturday: Somewhat longer dry periods are anticipated as the system continues to pull away, although enough lingering moisture and instability will remain for scattered showers. Skies should become partly sunny at times, with highs in the mid to upper 60s. A few showers may linger into Saturday evening before diminishing, with overnight temperatures falling into the upper 40s. Overall, Wednesday afternoon through Friday will provide the greatest opportunity for unsettled weather, although prolonged or heavy rainfall does not currently appear likely in the Saint John Valley. Conditions should gradually improve Saturday as the system moves farther east.

Long Range: Sun. Sep. 6 – Sat. Sep. 12
The latest Climate Prediction Center outlook favors above-normal temperatures and near-normal precipitation for Fort Kent and the Saint John Valley September 6–12. For Fort Kent, early September climatological normals average around 68°F for the high and 45°F for the low, with temperatures gradually trending downward as September progresses.

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.