September weather forecastOntario, OR
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Ontario, Oregon, with an average temperature varying between 80.6°F (27°C) and 55.2°F (12.9°C).Temperature
September's onset brings a slight change in high-temperatures, falling from a tropical 91.9°F (33.3°C) in August to a warm 80.6°F (27°C). Throughout September, Ontario acknowledges a distinct difference between its daytime highs and the steady low average of 55.2°F (12.9°C).Humidity
In Ontario, the average relative humidity in September is 36%.Rainfall
In September, the rain falls for 3.1 days. Throughout September, 0.2" (5mm) of precipitation is accumulated. In Ontario, during the entire year, the rain falls for 84.9 days and collects up to 9.29" (236mm) of precipitation.Snowfall
In Ontario, snow does not fall in May through October.Daylight
The average length of the day in September is 12h and 29min.On the first day of September, sunrise is at 7:12 am and sunset at 8:23 pm. On the last day of the month, sunrise is at 7:45 am and sunset at 7:29 pm MDT.
Sunshine
In Ontario, Oregon, the average sunshine in September is 9.5h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The UV index of 5 during September leads to these advisories:
Exercise care. People with light skin might get burns in fewer than 30 minutes. Around midday, solar radiation is most harmful; hence, exposure should be limited. During bright days, sunglasses that offer UVA and UVB defense are recommended.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Ontario, OR
- Average high temperature in September: 80.6°F
The warmest month (with the highest average high temperature) is July (93.2°F).
The months with the lowest average high temperature are January and December (36.1°F).
- Average low temperature in September: 55.2°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is December (23°F).
Average pressure in September
Ontario, OR
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.24"Hg).
The months with the lowest atmospheric pressure are June and August (29.92"Hg).
Average wind speed in September
Ontario, OR
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is April (6.5mph).
The calmest month (with the lowest average wind speed) is January (3.9mph).
Average humidity in September
Ontario, OR
- Average humidity in September: 36%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is August (29%).
Average rainfall in September
Ontario, OR
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is December (1.57").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in September
Ontario, OR
- Average rainfall days in September: 3.1 days
The month with the highest number of rainy days is March (13.3 days).
The month with the least rainy days is August (1.8 days).
Average snowfall in September
Ontario, OR
- Average snowfall in September: 0"
The month with the highest snowfall is December (5.35").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Ontario, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (7.4 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
Ontario, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 9h and 30min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).
Average sunshine days in September
Ontario, OR
- Average sunshine days in September: 26.1 days
The month with the most sunshine days is July (27.7 days).
The month with the least sunshine days is February (15.2 days).
Average UV index in September
Ontario, OR
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Ontario, OR
- Average cloud cover in September: 14
The months with the most cloud cover are January and December (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 8).
Average visibility in September
Ontario, OR
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
