September weather forecastPortal, AZ
September
Weather in September
The month of September in Portal, Arizona, indicates the onset of Fall, with declining temperatures being the dominant feature. The transition becomes evident from the lowering temperatures and shorter daylight hours. The rainfall sees a more significant drop from August to September, sliding down to about 1.22" (31mm). The decline in rainfall occurs in tandem with the reduction in humidity, leading to the cooler atmospheric conditions that presage the Fall season.Temperature
As September begins, there is a minor decrease in the average high-temperature, softly falling from a tropical 89.6°F (32°C) in August to a warm 84.2°F (29°C). Portal experiences an average nighttime temperature of 66.4°F (19.1°C) in the month of September.Heat index
September's heat index is calculated to be 84.2°F (29°C). Enduring exposure and ongoing activity could cause a sense of fatigue and subsequent heat cramps.The metrics for the heat index are tailored for both shady environments and light winds. Heat index values may rise by up to 15 Fahrenheit (8 Celsius) degrees when exposed to direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'feels like', ties air temperature with relative humidity to produce the perceived temperature sensation. This effect tends to be personal, with the weather perception differing among individuals due to variations in body mass, height, and exertion. Remember, direct sunlight exposure can heighten the heat impact and might increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Kids frequently ignore the importance of taking a break and rehydrating. Thirst is a late symptom of dehydration - thus, it is crucial to stay hydrated, especially during long-lasting physical activities.
Humidity
In September, the average relative humidity is 43%.Rainfall
In Portal, in September, during 9.5 rainfall days, 1.22" (31mm) of precipitation is typically accumulated. Throughout the year, there are 73.4 rainfall days, and 7.91" (201mm) of precipitation is accumulated.Snowfall
In Portal, snow does not fall in April through October.Daylight
The average length of the day in September is 12h and 21min.On the first day of the month, sunrise is at 5:52 am and sunset at 6:40 pm. On the last day of September, sunrise is at 6:10 am and sunset at 6:02 pm MST.
Sunshine
In Portal, the average sunshine in September is 10.7h.UV index
In September, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the maximum UV index of 6 translates into these guidelines:
Inhibit overexposure. Warding off sun damage is of utmost importance. 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. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Portal, AZ
- Average high temperature in September: 84.2°F
The warmest month (with the highest average high temperature) is June (92.8°F).
The month with the lowest average high temperature is December (54.5°F).
- Average low temperature in September: 66.4°F
The month with the highest average low temperature is July (73°F).
The coldest month (with the lowest average low temperature) is January (36.3°F).
Average pressure in September
Portal, AZ
- Average pressure in September: 29.94"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Portal, AZ
- Average wind speed in September: 7.7mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is January (7.1mph).
Average humidity in September
Portal, AZ
- Average humidity in September: 43%
The month with the highest relative humidity is December (51%).
The month with the lowest relative humidity is May (21%).
Average rainfall in September
Portal, AZ
- Average rainfall in September: 1.22"
The wettest month (with the highest rainfall) is July (1.81").
The driest month (with the least rainfall) is April (0.12").
Average rainfall days in September
Portal, AZ
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is July (15 days).
The month with the least rainy days is May (2.1 days).
Average snowfall in September
Portal, AZ
- Average snowfall in September: 0"
The month with the highest snowfall is December (0.79").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Portal, AZ
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (1.5 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Portal, AZ
- Average daylight in September: 12h and 18min
The month with the longest days is June (Average daylight: 14h and 12min).
The month with the shortest days is December (Average daylight: 10h and 6min).
- Average sunshine in September: 10h and 42min
The month with the most sunshine is June (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 7h and 0min).
Average sunshine days in September
Portal, AZ
- Average sunshine days in September: 16 days
The month with the most sunshine days is May (28.5 days).
The month with the least sunshine days is July (9.9 days).
Average UV index in September
Portal, AZ
- Average UV index in September: 6
The months with the highest UV index are May, June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 2).
Average cloud cover in September
Portal, AZ
- Average cloud cover in September: 16
The months with the most cloud cover are July and December (Cloud cover 20).
The month with the least cloud cover is May (Cloud cover 8).
Average visibility in September
Portal, AZ
- 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).
