September weather forecastIllmo, MO
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Illmo, Missouri, with an average temperature fluctuating between 61.3°F (16.3°C) and 81.1°F (27.3°C).Temperature
As Illmo, Missouri, welcomes September, the average high-temperature is noted at a moderately hot 81.1°F (27.3°C), closely aligning with the preceding month. An average temperature of 61.3°F (16.3°C) marks the nights in September.Heat index
September's heat index is computed to be a tropical 86°F (30°C). If activity and exposure persist, they could induce fatigue, leading to possible heat cramps.Heat index evaluations are typically in the context of light winds and shaded environments. The heat index has the potential to rise by 15 Fahrenheit (8 Celsius) degrees with direct sunshine exposure.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a value derived by merging air temperature with the humidity to convey how the climate feels. One's weather perception can be influenced by a range of factors including metabolic differences, being pregnant, and their level of physical activity. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Children regularly disregard the necessity to rest and replenish fluids. Thirst is a late symptom of dehydration - thus, maintaining hydration, particularly during long-lasting physical activities, is essential.
Humidity
In Illmo, the average relative humidity in September is 73%.Rainfall
The month with the least rainfall is September, when the rain falls for 11.4 days and typically collects 1.5" (38mm) of precipitation.Snowfall
In Illmo, snow does not fall in May through September.Daylight
In September, the average length of the day is 12h and 25min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:53 am and sunset at 6:42 pm CDT.
Sunshine
In September, the average sunshine is 9.7h.UV index
In Illmo, Missouri, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Guard yourself - Avoiding sunburn is suggested. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Illmo, MO
- Average high temperature in September: 81.1°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is January (41°F).
- Average low temperature in September: 61.3°F
The month with the highest average low temperature is July (69.4°F).
The coldest month (with the lowest average low temperature) is January (27.9°F).
Average pressure in September
Illmo, MO
- 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 (29.94"Hg).
Average wind speed in September
Illmo, MO
- Average wind speed in September: 6.2mph
The windiest months (with the highest average wind speed) are January and February (9.1mph).
The calmest months (with the lowest average wind speed) are July and August (5.7mph).
Average humidity in September
Illmo, MO
- Average humidity in September: 73%
The months with the highest relative humidity are March and May (78%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Illmo, MO
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is April (4.33").
The driest month (with the least rainfall) is September (1.5").
Average rainfall days in September
Illmo, MO
- Average rainfall days in September: 11.4 days
The month with the highest number of rainy days is July (17 days).
The month with the least rainy days is January (9.8 days).
Average snowfall in September
Illmo, MO
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.17").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Illmo, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (3.7 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Illmo, MO
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 9h and 42min
The month with the most sunshine is June (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 4h and 48min).
Average sunshine days in September
Illmo, MO
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is October (18.6 days).
The month with the least sunshine days is July (11.9 days).
Average UV index in September
Illmo, MO
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
Illmo, MO
- Average cloud cover in September: 27
The month with the most cloud cover is February (Cloud cover 48).
The months with the least cloud cover are June, August and September (Cloud cover 27).
Average visibility in September
Illmo, MO
- 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).
