Climate and monthly weather forecastGrand Isle, VT
Grand Isle, Vermont, USA - Climate and weather forecast by month. Detailed climate information with charts - average monthly weather with temperature, pressure, humidity, precipitation, wind, daylight, sunshine, visibility, and UV index data. Quite uniquely, Grand Isle experiences extensive daylight hours of up to 15.5 hours and an impressive average of 8.3 sunshine days in a month. The month with the least rainfall in Grand Isle is September, when the rain falls for 12.5 days and typically collects 1.81" (46mm) of precipitation.
Climate and monthly weather forecast
The climate of Grand Isle
Grand Isle's position in Vermont, USA, is unsurprisingly characterized by a Dfb Köppen climate classification, signifying a humid continental, no dry season, warm summer climatic condition. This climate type is typically associated with significant fluctuations in temperature, humidity, wind, and weather phenomena such as rain and snow, on an annual cycle.An examination of the climatic parameters reveals that throughout the year, temperatures in Grand Isle can range from a chilly 12°F (-11.1°C) to a high of 77.5°F (25.3°C). Notwithstanding, high humidity prevails all year round with an average value sitting at 80%. Rainfall is more or less consistent, with over 2" (51mm) expected in most months. Snowfall, on the other hand, is confined to the winter months and can peak to almost 9.5" (241mm).
Quite uniquely, Grand Isle experiences extensive daylight hours of up to 15.5 hours and an impressive average of 8.3 sunshine days in a month. Keeping an eye on the month of July reveals interesting climatic trends - it registers the highest temperatures, a lavish 10.4 hours of sunshine, and significantly, the highest UV index value of 5.
The best time to visit Grand Isle
Considering the weather elements, the best time to visit Grand Isle would be during the summer months from June to August. Average temperatures during this time can reach highs of 71.1°F (21.7°C) to 77.5°F (25.3°C) which is rather comfortable. Following the light, these months offer the most extended daylight hours, reaching a peak of 15.5 hours in June. To top it off, these months also record higher visibility at 6 miles, giving tourists the best conditions for exploration and sightseeing.The worst time to visit Grand Isle
Typically, the winter months from December to February make up the least advisable time to visit Grand Isle. During this period, temperatures can drop to a biting low of 12°F (-11.1°C). In addition, snowfall is extensive, with averages of up to 9.49" (241mm) in February. The daylight hours are also quite limited, dipping to as low as 8.9 hours in December. These conditions can potentially hamper travel and outdoor activities.Spring weather in Grand Isle
Spring ushers in the transition from the harsh winter towards milder weather. Between March and May, average temperatures can range from highs of 35.6°F (2°C) to 64.2°F (17.9°C) and lows of 22.5°F (-5.3°C) to 46°F (7.8°C). Rainfall totals from 2.24" (57mm) to 2.99" (76mm) making these months fairly wet. However, Grand Isle enjoys longer daylight hours during spring, moving from 12 daylight hours in March to 14.8 hours by May end.Summer weather in Grand Isle
Summer in Grand Isle is characterized by increasing temperatures, with averages fluctuating from the medium of 49.6°F (9.8°C) in June and reaching up to 77.5°F (25.3°C) in July. Minimum recorded temperatures rest between 52.9°F (11.6°C) and 59.4°F (15.2°C). The expected rainfall is highest in June at approximately 3.23" (82mm). Nevertheless, the highlight of summer is the sunshine hours - peaking at 10.4 hours in July.Autumn weather in Grand Isle
Autumn sees a cooling trend with temperatures starting at a high of 68.9°F (20.5°C) in September and descending to 41.9°F (5.5°C) by November. Corresponding minimum temperatures progress from 50.7°F (10.4°C) to 30.2°F (-1°C). Rainfall remains relatively constant, around the 2-inch mark, and the daylight hours decrease from 12.5 in September to 9.6 by November end. Interesting to note, although autumn sees a decline in temperature, it also witnesses the sunniest days with up to 15.3 in September.Winter weather in Grand Isle
Winter in Grand Isle is predictably cold. Average temperatures in this season oscillate between highs of 30.6°F (-0.8°C) in December and 27°F (-2.8°C) in February, and lows from 20.7°F (-6.3°C) down to 12°F (-11.1°C) also in February. Rainfall decreases compared to other seasons, with values between 2.32" (59mm) and 2.05" (52mm). Winter makes its mark with significant snowfall - December sees approximately 6.34" (161mm), and February tops at 9.49" (241mm).Weather in January
January in Grand Isle, Vermont is characteristic of its snowy winter weather, with temperatures that consistently stay in the chills. It is the coldest month of the year with temperatures ranging from 12°F (-11.1°C) to 24.3°F (-4.3°C). Weather in January »Weather in February
February brings slightly warmer temperatures as compared to January, but the snowfall continues to persist. With 9.49" (241mm) of snowfall throughout February, it stands out as the month with the maximum amount of snow decoration. Weather in February »Weather in March
March indicates a shift from winter to spring and displays a significant increase in temperatures. March undergoes a distinct change with temperatures rising by near eight°F from February, transforming the frozen landscapes into melty brooks and streams. Weather in March »Weather in April
In April, Grand Isle rapidly leaves winter behind with warmer temperatures and more rain replacing the snow. The change in weather brings warmth to the region; however, rainfall increases making it the wettest spring month. The landscapes come alive with colorful blooms and lush greenery replacing the barren winter scenes. Weather in April »Weather in May
May welcomes springtime with its characteristic warmth and vibrancy. The temperatures make a significant leap from the preceding months, laying the ground for potential summer activities. The lush greenery extends throughout May, giving the town its moniker as "the Green Mountain State." Songbirds return adding melody to the beautiful days, and nature walks become the town's favorite pastime. A clear escalation in the average high-temperature is witnessed in Grand Isle with the onset of May, advancing from a frosty 49.6°F (9.8°C) in April to an enjoyable 64.2°F (17.9°C). Weather in May »Weather in June
June is the doorway to summer in Grand Isle, Vermont. Temperatures continue to rise, and the days grow even longer, with sunlight pouring in for more than half the day. Outdoor activities ranging from hiking to fishing become popular sports with pleasant temperatures dominating the months. Weather in June »Weather in July
July is the peak of summer in Grand Isle, with temperatures reaching up to 77.5°F (25.3°C), the warmest of all the months. It showcases the town's sunniest weather, with a maximum UV index of 5 allowing for sunshine-filled days. Weather in July »Weather in August
August brings a slight easing off on temperatures from July. Although August sees a reduction in temperature, it remains a comfortable time in Grand Isle. The days are still long and sunny, allowing plenty of time to engage in outdoor activities. Weather in August »Weather in September
September indicates the arrival of fall, with temperatures starting to decline. As the air becomes a tad crisper and temperatures start dipping, it is a signal that summer is winding down. The sway between the remaining summer warmth and incoming autumn cool generates a dynamic weather pattern. Weather in September »Weather in October
October progresses more into fall with significantly cooler temperatures compared to September. It is characterized by a host of fall festivities, taking advantage of the typical fall season's unique weather. The beautiful foliage in Grand Isle during this time is a sight to behold. Weather in October »Weather in November
November's weather in Grand Isle indicates a transition from fall to winter. There is a noticeable drop in temperatures, and the first snowfalls can be expected. The landscape steadily transitions from the vibrant shades of fall to the starker contrasts of winter. Weather in November »Weather in December
December brings the return of the all-encompassing winter to Grand Isle. The snowfall continues to increase, with averages reaching 6.34" (161mm), second only to February's record. Life slows down a bit as the town readies itself for the chill of the coming months. Weather in December »Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Grand Isle, Vermont, experiences its lowest temperatures in January, with an average peak of 24.3°F (-4.3°C) and a low of 12°F (-11.1°C).
January and February, with an average relative humidity of 87%, are most humid months in Grand Isle, Vermont.
In Grand Isle, Vermont, during the entire year, the rain falls for 176.9 days and collects up to 29.88" (759mm) of precipitation.
Months with snowfall are January through May, October through December.
In Grand Isle, Vermont, during the entire year, snow falls for 81.9 days and aggregates up to 36.77" (934mm) of snow.
February is the month with the most snowfall in Grand Isle, Vermont. Snow falls for 19.2 days and accumulates 9.49" (241mm) of snow.
The month with the least sunshine in Grand Isle is February, with an average of 3.4h of sunshine.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from EDT to EST.
The months with the lowest humidity in Grand Isle, Vermont, are April and May, with an average relative humidity of 76%.
May through August, with an average maximum UV index of 5, are months with the highest UV index.
June is the month with the most rainfall. Rain falls for 18.8 days and accumulates 3.23" (82mm) of precipitation.
June through September are months without snowfall.
June has the longest days of the year, with an average of 15h and 30min of daylight.
In Grand Isle, Vermont, temperatures reach their average annual highs in July, measuring 77.5°F (25.3°C) and a minimum average of 59.4°F (15.2°C).
With an average of 10.5h of sunshine, August has the most sunshine of the year in Grand Isle.
The month with the least rainfall in Grand Isle is September, when the rain falls for 12.5 days and typically collects 1.81" (46mm) of precipitation.
The month with the shortest days in Grand Isle is December, with an average of 8h and 54min of daylight.
With an average maximum UV index of 1, December is the month with the lowest UV index in Grand Isle.
Average temperature
Grand Isle, VT
The warmest month (with the highest average high temperature) is July (77.5°F).
The month with the lowest average high temperature is January (24.3°F).
The month with the highest average low temperature is July (59.4°F).
The coldest month (with the lowest average low temperature) is January (12°F).
Average pressure
Grand Isle, VT
- Average pressure in January:
30.02"Hg - Average pressure in February:
30.01"Hg - Average pressure in March:
30.05"Hg - Average pressure in April:
29.96"Hg - Average pressure in May:
29.97"Hg - Average pressure in June:
29.91"Hg
- Average pressure in July:
29.93"Hg - Average pressure in August:
29.96"Hg - Average pressure in September:
30.04"Hg - Average pressure in October:
30"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.04"Hg
The month with the highest atmospheric pressure is November (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed
Grand Isle, VT
- Average wind speed in January:
7.6mph - Average wind speed in February:
7.3mph - Average wind speed in March:
7.6mph - Average wind speed in April:
8mph - Average wind speed in May:
7.1mph - Average wind speed in June:
6.4mph
- Average wind speed in July:
6.1mph - Average wind speed in August:
6.1mph - Average wind speed in September:
6.2mph - Average wind speed in October:
7.1mph - Average wind speed in November:
7.6mph - Average wind speed in December:
7.4mph
The windiest month (with the highest average wind speed) is April (8mph).
The calmest months (with the lowest average wind speed) are July and August (6.1mph).
Average humidity
Grand Isle, VT
The months with the highest relative humidity are January and February (87%).
The months with the lowest relative humidity are April and May (76%).
Average rainfall
Grand Isle, VT
- Average rainfall in January:
2.05" - Average rainfall in February:
1.93" - Average rainfall in March:
2.24" - Average rainfall in April:
2.64" - Average rainfall in May:
2.99" - Average rainfall in June:
3.23"
- Average rainfall in July:
2.76" - Average rainfall in August:
2.95" - Average rainfall in September:
1.81" - Average rainfall in October:
2.68" - Average rainfall in November:
2.28" - Average rainfall in December:
2.32"
The wettest month (with the highest rainfall) is June (3.23").
The driest month (with the least rainfall) is September (1.81").
Average rainfall days
Grand Isle, VT
- Average rainfall days in January:
9.4 days - Average rainfall days in February:
9.5 days - Average rainfall days in March:
13.7 days - Average rainfall days in April:
17.8 days - Average rainfall days in May:
17.8 days - Average rainfall days in June:
18.8 days
- Average rainfall days in July:
18.5 days - Average rainfall days in August:
18 days - Average rainfall days in September:
12.5 days - Average rainfall days in October:
16.4 days - Average rainfall days in November:
12.2 days - Average rainfall days in December:
12.3 days
The month with the highest number of rainy days is June (18.8 days).
The month with the least rainy days is January (9.4 days).
Average snowfall
Grand Isle, VT
- Average snowfall in January:
7.95" - Average snowfall in February:
9.49" - Average snowfall in March:
5.94" - Average snowfall in April:
2.28" - Average snowfall in May:
0.04" - Average snowfall in June:
0"
The month with the highest snowfall is February (9.49").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Grand Isle, VT
- Average snowfall days in January:
19.4 days - Average snowfall days in February:
19.2 days - Average snowfall days in March:
13.4 days - Average snowfall days in April:
5.1 days - Average snowfall days in May:
0.3 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
1.5 days - Average snowfall days in November:
6.9 days - Average snowfall days in December:
16.1 days
The month with the highest number of snowfall days is January (19.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Grand Isle, VT
- Average daylight in January:
9h and 18min - Average daylight in February:
10h and 30min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 30min - Average daylight in May:
14h and 48min - Average daylight in June:
15h and 30min
- Average daylight in July:
15h and 12min - Average daylight in August:
14h and 0min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 0min - Average daylight in November:
9h and 36min - Average daylight in December:
8h and 54min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in January:
3h and 36min - Average sunshine in February:
3h and 24min - Average sunshine in March:
5h and 0min - Average sunshine in April:
7h and 30min - Average sunshine in May:
8h and 48min - Average sunshine in June:
9h and 12min
- Average sunshine in July:
10h and 24min - Average sunshine in August:
10h and 30min - Average sunshine in September:
9h and 6min - Average sunshine in October:
5h and 24min - Average sunshine in November:
4h and 54min - Average sunshine in December:
3h and 42min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The month with the least sunshine is February (Average sunshine: 3h and 24min).
Average sunshine days
Grand Isle, VT
- Average sunshine days in January:
8.3 days - Average sunshine days in February:
6.5 days - Average sunshine days in March:
8.4 days - Average sunshine days in April:
8.7 days - Average sunshine days in May:
11.3 days - Average sunshine days in June:
9.3 days
- Average sunshine days in July:
9.3 days - Average sunshine days in August:
10.3 days - Average sunshine days in September:
15.3 days - Average sunshine days in October:
11.8 days - Average sunshine days in November:
13.5 days - Average sunshine days in December:
8.3 days
The month with the most sunshine days is September (15.3 days).
The month with the least sunshine days is February (6.5 days).
Average UV index
Grand Isle, VT
The months with the highest UV index are May, June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).
Average cloud cover
Grand Isle, VT
The month with the most cloud cover is February (Cloud cover 66).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility
Grand Isle, VT
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January and February (4mi).
