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Grand Isle, ME Weather Forecast for 5-Days

Updated: Mon May 18th 2026 8:15 PM EDT

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Grand Isle, ME Weather – 5-18 – Sunny
69° / 39°
Sunny
Daytime highs will reach 69°F with lows dropping to 39°F in Grand Isle, where it will be sunny. Winds will be light at 9mph and gusts of 12.9mph at 11 PM. Humidity levels should be comfortable, sitting around 40% on average, the maximum being 54% at 11 PM and 38% being its lowest at 9 PM. Barometric pressure is its highest of 30.07inHg at 9 PM, a lowest point of 30inHg at 11 PM with an avg 30.04inHg.
Grand Isle, ME Weather – 5-19 – Moderate Rain
57° / 52°

Weather Tomorrow

Moderate Rain
Daytime highs will reach 57°F with lows dropping to 52°F in Grand Isle, where periods of rain are likely. The chance of rain is 89% with an estimated 0.29in. Winds will be light at 7mph and gusts of 10.6mph at 12 AM. High humidity with average of 88% is anticipated, the maximum being 99% at 11 PM and 61% being its lowest at 2 AM. Barometric pressure is its highest of 29.99inHg at 12 AM, a lowest point of 29.77inHg at 11 PM with an avg 29.87inHg.
Grand Isle, ME Weather – 5-20 – Scattered Showers
70° / 41°
Scattered Showers
Highs will reach 70°F with lows near 41°F in Grand Isle, where scattered showers are. The chance of rain is 82% with an estimated 0.06in. Wind will be moderate, blowing around 19mph on average and gusts of 26.6mph at 10 PM. The humidity will be on the higher side, averaging about 78%, the maximum being 99% at 12 AM and 49% being its lowest at 3 PM. Barometric pressure is its highest of 29.92inHg at 11 PM, a lowest point of 29.58inHg at 12 PM with an avg 29.7inHg.
Grand Isle, ME Weather – 5-21 – Partly Cloudy
51° / 35°
Partly Cloudy
Highs will reach 51°F with lows near 35°F in Grand Isle, where cloudy skies are. Wind will be moderate, blowing around 16mph on average and gusts of 23mph at 12 AM. Humidity levels should be comfortable, sitting around 53% on average, the maximum being 73% at 5 AM and 37% being its lowest at 2 PM. Barometric pressure is its highest of 30.18inHg at 9 PM, a lowest point of 29.94inHg at 12 AM with an avg 30.09inHg.
Grand Isle, ME Weather – 5-22 – Sunny
54° / 31°
Sunny
It will be sunny in Grand Isle, with a high of 54°F and a low of 31°F. Wind will be moderate, blowing around 18mph on average and gusts of 20.6mph at 1 PM. Humidity levels should be comfortable, sitting around 51% on average, the maximum being 70% at 5 AM and 36% being its lowest at 3 PM. Barometric pressure is its highest of 30.28inHg at 11 PM, a lowest point of 30.13inHg at 4 PM with an avg 30.18inHg.
Grand Isle, ME Weather – 5-23 – Sunny
59° / 30°
Sunny
Highs will reach 59°F with lows near 30°F in Grand Isle, where a sunny day is. Winds will be light at 9mph and gusts of 12.2mph at 1 AM. The humidity will be on the higher side, averaging about 64%, the maximum being 82% at 5 AM and 39% being its lowest at 2 PM. Barometric pressure is its highest of 30.47inHg at 11 PM, a lowest point of 30.3inHg at 12 AM with an avg 30.4inHg.

Currently

Overcast 58°F
30.03 inHg.
Barometer
27%
Humidity
SSE 11.9 mph
Wind
Overcast

5 Day Forecast Nearby

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