May weather forecast
Isle Royale National Park, MI

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Calm evening waters at the Rock Harbor in Isle Royale National Park, Michigan, USA
Calm evening waters at the Rock Harbor in Isle Royale National Park, Michigan, USA

Weather in May

May ushers in the true essence of spring with its mild and comfortable climate. It offers a respite from the long, dreary winter. Following April, May continues the trend of increased daylight hours. Rainfall is expected to be slightly higher than the previous month, making the location greener. The temperature exhibits a considerable rise, averaging from 37°F (2.8°C) to 59°F (15°C), engendering the warmth of spring.

Temperature

Entering May, Isle Royale National Park sees a temperature rise, with the average high-temperature advancing from April's chilly 46.4°F (8°C) to a refreshing 59°F (15°C). Despite considerable daily temperature swings, a steady low-temperature average of 37.4°F (3°C) is noted in Isle Royale National Park throughout May.

Rainfall

In Isle Royale National Park, in May, during 10 rainfall days, 2.68" (68mm) of precipitation is typically accumulated. In Isle Royale National Park, during the entire year, the rain falls for 125 days and collects up to 30.55" (776mm) of precipitation.

Ocean temperature

In May, the average ocean temperature is 37.4°F (3°C).
Note: For swimming, this is considered life-threatening and very dangerous. The water feels painfully cold, and hyperventilation quickly occurs. A specialized swimsuit is mandatory to reduce thermal damage.

Daylight

In Isle Royale National Park, the average length of the day in May is 15h and 12min.
On the first day of May, sunrise is at 6:35 am and sunset at 9:09 pm. On the last day of the month, sunrise is at 6:00 am and sunset at 9:46 pm EDT.

Sunshine

In Isle Royale National Park, the average sunshine in May is 8h.

UV index

The average daily maximum UV index in May in Isle Royale National Park is 6. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum UV index of 6 during May leads to these instructions:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
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Frequently asked questions

What are May temperatures in Isle Royale National Park?

In Isle Royale National Park, 59°F (15°C) is the average high-temperature and 37.4°F (3°C) is the average low-temperature during May.

How many days does it rain in May in Isle Royale National Park?

In Isle Royale National Park, during May, the rain falls for 10 days and regularly aggregates up to 2.68" (68mm) of precipitation.

What is the water temperature in May in Isle Royale National Park?

In May, the average ocean temperature in Isle Royale National Park is 37.4°F (3°C). For swimming, this is considered life-threatening and very dangerous. The water feels painfully cold, and hyperventilation quickly occurs. A specialized swimsuit is mandatory to reduce thermal damage.

What is the average length of the day in May in Isle Royale National Park?

In Isle Royale National Park, the average day length in May is 15h and 12min.

When is the sunrise / sunset in May in Isle Royale National Park?

In May, on the first day of the month, sunrise is at 6:35 am and sunset at 9:09 pm. On the last day of the month, sunrise is at 6:00 am and sunset at 9:46 pm EDT.

How long on average sun shines in May in Isle Royale National Park?

In May, the average sunshine duration in Isle Royale National Park, Michigan, is 8h.

How high is the UV index in May in Isle Royale National Park?

In May, the average daily maximum UV index in Isle Royale National Park is 6. A UV Index value of 6 to 7 symbolizes a high health risk from unprotected exposure to UV radiation.
Average high temperature
Average rainfall days
Average daylight
Average sunshine
Average UV index

Average temperature in May
Isle Royale National Park, MI

Average temperature in May - Isle Royale National Park, MI
  • Average high temperature in May: 59°F

The warmest month (with the highest average high temperature) is July (75°F).
The month with the lowest average high temperature is January (18°F).

  • Average low temperature in May: 37°F

The month with the highest average low temperature is July (54°F).
The coldest month (with the lowest average low temperature) is January (0°F).

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Average rainfall in May
Isle Royale National Park, MI

Average rainfall in May - Isle Royale National Park, MI
  • Average rainfall in May: 2.7"

The wettest month (with the highest rainfall) is September (3.4").
The driest month (with the least rainfall) is February (1.5").

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Average rainfall days in May
Isle Royale National Park, MI

Average rainfall days in May - Isle Royale National Park, MI
  • Average rainfall days in May: 10 days

The months with the highest number of rainy days are June and September (13 days).
The months with the least rainy days are February and April (8 days).

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Average sea temperature in May
Isle Royale National Park, MI

Average sea temperature in May - Isle Royale National Park, MI
  • Average sea temperature in May: 37°F

The best month for swimming (with the highest average sea temperature) is August (55°F).
The coldest months (with the lowest average sea temperature) are January, February, March and April (36°F).

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Average daylight in May /
Average sunshine in May
Isle Royale National Park, MI

Average daylight in May / Average sunshine in May - Isle Royale National Park, MI
  • Average daylight in May: 15h and 1min

The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in May: 8h

The month with the most sunshine is July (Average sunshine: 10h).
The months with the least sunshine are November and December (Average sunshine: 3h).

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Average UV index in May
Isle Royale National Park, MI

Average UV index in May - Isle Royale National Park, MI
  • Average UV index in May: 6

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 1).

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Isle Royale National Park, Michigan, USA

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