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 beginning of September, Alton's high-temperatures register at a still hot 87.8°F (31°C), closely mirroring the preceding month. In September, Alton reports a consistent average low-temperature of 70.7°F (21.5°C) during the nights.Heat index
September's average heat index is calculated to be an extremely hot 104°F (40°C). Adopt additional preventive measures, heat cramps and heat exhaustion are potential outcomes. Prolonged activity may trigger heatstroke.When assessing, remember that heat index measurements are for light winds and shaded spots. 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 'real feel' or 'feels like', binds temperature metrics with humidity values to give a sense of the actual warmth. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely vital to babies and toddlers. Kids are generally in more danger than adults because they perspire less. Their large skin surface area compared to their small bodies and the excessive heat due to their actions raises their risk.
Through perspiration, the body has a natural mechanism to eliminate excessive heat via sweat evaporation. Under conditions of increased relative humidity, the evaporation rate lessens, causing the body to retain more heat than under less humid conditions. Heat-related challenges, like dehydration, can be anticipated when body heat isn't managed effectively.
Humidity
August, September and December, with an average relative humidity of 77%, are the most humid months.Rainfall
In September, the rain falls for 19.5 days. Throughout September, 3.03" (77mm) of precipitation is accumulated. In Alton, during the entire year, the rain falls for 173.6 days and collects up to 31.3" (795mm) of precipitation.Snowfall
January, March through December are months without snowfall.Daylight
In September, the average length of the day is 12h and 20min.On the first day of the month, sunrise is at 7:09 am and sunset at 7:54 pm. On the last day of September, sunrise is at 7:25 am and sunset at 7:18 pm EDT.
Sunshine
In September, the average sunshine is 8.5h.UV index
In Alton, Florida, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum UV index of 6 during September translates into these guidelines:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot does it get in September?
What are the most humid months?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does Alton have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Alton have in September?
What is the UV index intensity in September?
Average temperature in September
Alton, FL
- Average high temperature in September: 87.8°F
The warmest months (with the highest average high temperature) are July and August (91.2°F).
The month with the lowest average high temperature is January (62.2°F).
- Average low temperature in September: 70.7°F
The month with the highest average low temperature is August (74.8°F).
The coldest month (with the lowest average low temperature) is January (44.2°F).
Average pressure in September
Alton, FL
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.98"Hg).
Average wind speed in September
Alton, FL
- Average wind speed in September: 5mph
The windiest months (with the highest average wind speed) are March and April (6.5mph).
The calmest months (with the lowest average wind speed) are July and August (4.8mph).
Average humidity in September
Alton, FL
- Average humidity in September: 77%
The months with the highest relative humidity are August, September and December (77%).
The month with the lowest relative humidity is May (70%).
Average rainfall in September
Alton, FL
- Average rainfall in September: 3.03"
The wettest month (with the highest rainfall) is August (4.57").
The driest month (with the least rainfall) is November (1.14").
Average rainfall days in September
Alton, FL
- Average rainfall days in September: 19.5 days
The month with the highest number of rainy days is August (25.5 days).
The month with the least rainy days is November (7.2 days).
Average snowfall days in September
Alton, FL
- 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
Alton, FL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).
- Average sunshine in September: 8h and 3min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
Alton, FL
- Average sunshine days in September: 8.9 days
The month with the most sunshine days is November (21.5 days).
The month with the least sunshine days is August (4.3 days).
Average UV index in September
Alton, FL
- 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 January (UV index 3).
Average cloud cover in September
Alton, FL
- Average cloud cover in September: 34
The month with the most cloud cover is December (Cloud cover 40).
The month with the least cloud cover is October (Cloud cover 29).
Average visibility in September
Alton, FL
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, May, June, July, August, October, November and December (6mi).
The month with the lowest visibility is September (5mi).
Alton, Florida, USA
Weather forecast for your location
2. Allow the app to use your location