Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Upon the onset of September, Ontario witnesses an average high-temperature of a still tropical 88.2°F (31.2°C), showing a close resemblance to the prior month. Ontario reports a considerable drop from daytime temperatures in September, recording an average nighttime figure of 63.5°F (17.5°C).Heat index
The average heat index in September is appraised at a hot 89.6°F (32°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.When assessing, remember that heat index measurements are for light winds and shaded spots. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is a composite of temperature and humidity figures to convey how warm it feels. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. Keep it in mind, direct sunlight can augment the heat you experience, possibly pushing the heat index up by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
Humidity
The average relative humidity in September is 44%.Rainfall
In September, in Ontario, the rain falls for 2.5 days. Throughout September, 0.12" (3mm) of precipitation is accumulated. Throughout the year, in Ontario, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.Snowfall
January, March through December are months without snowfall in Ontario.Daylight
The average length of the day in September in Ontario is 12h and 22min.On the first day of the month, sunrise is at 6:24 am and sunset at 7:15 pm. On the last day of September, sunrise is at 6:44 am and sunset at 6:35 pm PDT.
Sunshine
In Ontario, California, the average sunshine in September is 10.7h.UV index
In September, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for average individuals.Note: In September, the maximum UV index of 6 transforms into these recommendations:
Sustain precautions and conform to sun safety norms. Preventing sunburn is necessary. The Sun's UV radiation is most intense from 10 a.m. to 4 p.m. Try to avoid direct sun exposure during these hours. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in Ontario in September?
What is the average humidity in September in Ontario?
How much does it rain in Ontario in September?
When it does not snow in Ontario?
How many hours of daylight does Ontario have in September?
When are sunrise and sunset in September in Ontario?
How many hours of sunshine does Ontario have in September?
What is the UV index intensity in September in Ontario?
Average temperature in September
Ontario, CA
- Average high temperature in September: 88.2°F
The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).
- Average low temperature in September: 63.5°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).
Average pressure in September
Ontario, CA
- Average pressure in September: 29.88"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Ontario, CA
- Average wind speed in September: 4.4mph
The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in September
Ontario, CA
- Average humidity in September: 44%
The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).
Average rainfall in September
Ontario, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Ontario, CA
- Average rainfall days in September: 2.5 days
The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in September
Ontario, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
Ontario, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 10h and 4min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days in September
Ontario, CA
- Average sunshine days in September: 25.4 days
The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).
Average UV index in September
Ontario, CA
- Average UV index in September: 6
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in September
Ontario, CA
- Average cloud cover in September: 6
The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
Ontario, CA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Ontario, California, USA
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