August 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 August

In August, the weather begins to mellow down from the peak in July. However, the summer heat still predominates, although slightly less intense than July. Rainfall shows a marginal increase, retaining moisture within the environment. Daylight hours start to decline, hinting at the upcoming autumn. Despite the decrease in sunlight, temperatures still oscillate between 52°F (11.1°C) and 72°F (22.2°C), maintaining the warmth.

Temperature

The transition into August marks the average high-temperature at an agreeable 71.6°F (22°C), differing minimally from July's 75.2°F (24°C). Throughout August, the nighttime temperature averages to a fresh 51.8°F (11°C).

Rainfall

In August, in Isle Royale National Park, the rain falls for 12 days. Throughout August, 3.31" (84mm) of precipitation is accumulated. In Isle Royale National Park, Michigan, during the entire year, the rain falls for 125 days and collects up to 30.55" (776mm) of precipitation.

Ocean temperature

August is the month with the warmest seawater in Isle Royale National Park, with an average ocean temperature of 55.4°F (13°C).
Note: At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

Daylight

In August, the average length of the day is 14h and 14min.
On the first day of the month, sunrise is at 6:32 am and sunset at 9:30 pm. On the last day of August, in Isle Royale National Park, sunrise is at 7:13 am and sunset at 8:38 pm EDT.

Sunshine

The average sunshine in August in Isle Royale National Park is 8h.

UV index

The average daily maximum UV index in August is 6. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV radiation for the average person.
Note: In August, the maximum UV index of 6 translates into these guidelines:
Deter overexposure. Protecting against the sun's effects is essential. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
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Frequently asked questions

What are August temperatures in Isle Royale National Park?

The average high-temperature, in August, in Isle Royale National Park, is 71.6°F (22°C), while the average low-temperature is 51.8°F (11°C).

How much does it rain in Isle Royale National Park in August?

In Isle Royale National Park, in August, during 12 rainfall days, 3.31" (84mm) of precipitation is typically accumulated.

What month is the ocean warmest in Isle Royale National Park?

The month with the warmest seawater is August, with an average ocean temperature of 55.4°F (13°C).

How cold is the water in August in Isle Royale National Park?

In August, the average ocean temperature is 55.4°F (13°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

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

The average day length in August is 14h and 14min.

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

On the first day of August in Isle Royale National Park, Michigan, sunrise is at 6:32 am and sunset at 9:30 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 8:38 pm EDT.

How many hours of sunshine does Isle Royale National Park have in August?

In August, the average sunshine duration is 8h.

What is the UV index reading in August in Isle Royale National Park?

In August, the average daily maximum UV index in Isle Royale National Park is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from exposure to Sun's UV rays.
Average rainfall days
Average daylight
Average sunshine
Average UV index

Average temperature in August
Isle Royale National Park, MI

Average temperature in August - Isle Royale National Park, MI
  • Average high temperature in August: 72°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 August: 52°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 August
Isle Royale National Park, MI

Average rainfall in August - Isle Royale National Park, MI
  • Average rainfall in August: 3.3"

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 August
Isle Royale National Park, MI

Average rainfall days in August - Isle Royale National Park, MI
  • Average rainfall days in August: 12 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 August
Isle Royale National Park, MI

Average sea temperature in August - Isle Royale National Park, MI
  • Average sea temperature in August: 55°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 August /
Average sunshine in August
Isle Royale National Park, MI

Average daylight in August / Average sunshine in August - Isle Royale National Park, MI
  • Average daylight in August: 14h 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 August: 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 August
Isle Royale National Park, MI

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