Grand Rapids
Michigan, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Grand Rapids, MI

The vast cityscape of Grand Rapids, a moderately large town in Michigan, and two visible bridges across the river, on a warm and cool, cloudy day
The vast cityscape of Grand Rapids, a moderately large town in Michigan, and two visible bridges across the river, on a warm and cool, cloudy day
September, the first month of the autumn, in Grand Rapids, is still a pleasant month, with average temperature ranging between max 72°F (22.2°C) and min 54°F (12.2°C).

Temperature

In Grand Rapids, the average high-temperature marginally drops, from a moderately hot 78.6°F (25.9°C) in August, to an agreeable 72°F (22.2°C). The average low-temperature, in Grand Rapids, is 54°F (12.2°C).

Humidity

The average relative humidity is 77%.

Rainfall

In Grand Rapids, during September, the rain falls for 6.6 days and regularly aggregates up to 0.63" (16mm) of precipitation. In Grand Rapids, during the entire year, the rain falls for 103.5 days and collects up to 9.02" (229mm) of precipitation.

Snowfall

May through October are months without snowfall in Grand Rapids, Michigan.

Daylight

In Grand Rapids, the average length of the day in September is 12.5h.

Sunshine

In September, the average sunshine is 8.2h.

UV index

In Grand Rapids, Michigan, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to the Sun's UV rays for ordinary individuals.
Note: In September, the average maximum UV index of 4 translate into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.

What is the temperature in September in Grand Rapids?

In Grand Rapids, in September, the average high-temperature is 72°F (22.2°C), and the average low-temperature is 54°F (12.2°C).

What is the average humidity in September in Grand Rapids?

In September, the average relative humidity in Grand Rapids is 77%.

How much does it rain in Grand Rapids in September?

In Grand Rapids, in September, during 6.6 rainfall days, 0.63" (16mm) of precipitation is typically accumulated.

When it does not snow in Grand Rapids?

May through October are months without snowfall in Grand Rapids.

What is the average length of the day in September in Grand Rapids?

The average length of the day in September in Grand Rapids, Michigan, is 12.5h.

How many hours of sunshine does Grand Rapids have in September?

The average sunshine in September is 8.2h.

How high is the UV index in September in Grand Rapids?

In September, the average daily maximum UV index in Grand Rapids is 4. A UV Index reading of 3 to 5 represents a medium health risk from the exposure to the Sun's UV radiation.
Average temperature in September - Grand Rapids, MI
  • Average high temperature in September: 72°F

The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (27.7°F).

  • Average low temperature in September: 54°F

The month with the highest average low temperature is July (61.5°F).
The coldest month (with the lowest average low temperature) is January (18.7°F).

Average humidity in September - Grand Rapids, MI
  • Average humidity in September: 77%

The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is April (75%).

Average rainfall in September - Grand Rapids, MI
  • Average rainfall in September: 0.63"

The wettest month (with the highest rainfall) is May (1.14").
The driest month (with the lowest rainfall) is March (0.47").

Average rainfall days in September - Grand Rapids, MI
  • Average rainfall days in September: 6.6 days

The month with the highest number of rainy days is May (13 days).
The month with the lowest number of rainy days is February (3.8 days).

Average snowfall in September - Grand Rapids, MI
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.57").
Months with the lowest snowfall are May, June, July, August, September and October (0").

Average snowfall days in September - Grand Rapids, MI
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (11.5 days).
Months with the lowest number of snowfall days are May, June, July, August and September (0 days).

Average daylight in September / Average sunshine in September - Grand Rapids, MI
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.3h).
The month with shortest days is December (Average daylight: 9.1h).

  • Average sunshine in September: 8.2h

The month with most sunshine is July (Average sunshine: 10.3h).
The month with least sunshine is January (Average sunshine: 2.3h).

Average UV index in September - Grand Rapids, MI
  • Average UV index in September: 4

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January and December (UV index 1).