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 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
With the onset of September, Altoona's climate undergoes a slight change as the average high-temperature moves from 81.1°F (27.3°C) in August to a still warm 75.4°F (24.1°C). During the nights in September, an average low-temperature of 55.9°F (13.3°C) is observed.Humidity
The average relative humidity in September is 76%.Rainfall
In Altoona, in September, it is raining for 7.2 days, with typically 0.63" (16mm) of accumulated precipitation. In Altoona, Iowa, during the entire year, the rain falls for 79 days and collects up to 5.94" (151mm) of precipitation.Snowfall
In Altoona, snow does not fall in May through September.Daylight
In September, the average length of the day in Altoona is 12h and 28min.On the first day of September in Altoona, sunrise is at 6:40 am and sunset at 7:46 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:56 pm CDT.
Sunshine
In Altoona, the average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Frequently asked questions
What is the temperature in September in Altoona?
What is the average humidity in September in Altoona?
How much does it rain in Altoona in September?
When it does not snow in Altoona?
Does it snow in Altoona in September?
How many hours of daylight does Altoona have in September?
When are sunrise and sunset in September in Altoona?
How many hours of sunshine does Altoona have in September?
How high is the UV index in September in Altoona?
Average temperature in September
Altoona, IA
- Average high temperature in September: 75.4°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (27.5°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (14.4°F).
Average pressure in September
Altoona, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Altoona, IA
- Average wind speed in September: 8mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.9mph).
Average humidity in September
Altoona, IA
- Average humidity in September: 76%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Altoona, IA
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is May (0.98").
The driest months (with the least rainfall) are January, February and December (0.24").
Average rainfall days in September
Altoona, IA
- Average rainfall days in September: 7.2 days
The month with the highest number of rainy days is May (11.6 days).
The month with the least rainy days is January (1.8 days).
Average snowfall in September
Altoona, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.91").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Altoona, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.2 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Altoona, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Altoona, IA
- Average sunshine days in September: 21 days
The month with the most sunshine days is December (25.5 days).
The month with the least sunshine days is June (15.5 days).
Average UV index in September
Altoona, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Altoona, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July and September (Cloud cover 29).
Average visibility in September
Altoona, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Altoona, Iowa, USA
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