September weather forecastGrand Rapids, OR
September
Weather in September
September, the first month of the autumn in Grand Rapids, is also an agreeable month, with an average temperature fluctuating between 70.3°F (21.3°C) and 47.7°F (8.7°C).Temperature
September's onset brings a negligible change in high-temperatures, falling from a moderately hot 77°F (25°C) in August to a pleasant 70.3°F (21.3°C). Throughout September, Grand Rapids acknowledges a distinct difference between its daytime highs and the steady low average of 47.7°F (8.7°C).Humidity
In September, the average relative humidity is 79%.Rainfall
In Grand Rapids, during September, the rain falls for 12.2 days and regularly aggregates up to 1.81" (46mm) of precipitation. Throughout the year, there are 184.4 rainfall days, and 36.61" (930mm) of precipitation is accumulated.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September is 12h and 31min.On the first day of the month, sunrise is at 6:36 am and sunset at 7:51 pm. On the last day of September, sunrise is at 7:12 am and sunset at 6:55 pm PDT.
Sunshine
In Grand Rapids, the average sunshine in September is 8.4h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 3 in September interprets into the following recommendations:
Be mindful. Those with pale skin might receive burns in fewer than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Grand Rapids, OR
- Average high temperature in September: 70.3°F
The warmest month (with the highest average high temperature) is August (77°F).
The month with the lowest average high temperature is December (42.1°F).
- Average low temperature in September: 47.7°F
The month with the highest average low temperature is August (50.7°F).
The coldest month (with the lowest average low temperature) is December (32.9°F).
Average pressure in September
Grand Rapids, OR
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.02"Hg).
Average wind speed in September
Grand Rapids, OR
- Average wind speed in September: 3.9mph
The windiest months (with the highest average wind speed) are January, March and November (4.8mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).
Average humidity in September
Grand Rapids, OR
- Average humidity in September: 79%
The month with the highest relative humidity is November (89%).
The month with the lowest relative humidity is July (73%).
Average rainfall in September
Grand Rapids, OR
- Average rainfall in September: 1.81"
The wettest month (with the highest rainfall) is January (5.79").
The driest months (with the least rainfall) are July and August (0.51").
Average rainfall days in September
Grand Rapids, OR
- Average rainfall days in September: 12.2 days
The month with the highest number of rainy days is March (21.7 days).
The month with the least rainy days is July (6 days).
Average snowfall in September
Grand Rapids, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.94").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Grand Rapids, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.4 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Grand Rapids, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in September: 8h and 24min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is February (Average sunshine: 3h and 18min).
Average sunshine days in September
Grand Rapids, OR
- Average sunshine days in September: 15.6 days
The month with the most sunshine days is July (22.1 days).
The months with the least sunshine days are February and March (7.6 days).
Average UV index in September
Grand Rapids, OR
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Grand Rapids, OR
- Average cloud cover in September: 43
The months with the most cloud cover are February and March (Cloud cover 67).
The month with the least cloud cover is August (Cloud cover 34).
Average visibility in September
Grand Rapids, OR
- Average visibility in September: 4mi
The months with the highest visibility are July and August (5mi).
The months with the lowest visibility are January, February, March, April, May, June, September, October, November and December (4mi).
