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
The average high-temperature slightly decreases in September, shifting from a moderately hot 81.7°F (27.6°C) in August to a still warm 76.3°F (24.6°C). Throughout the month of September, the nighttime temperature dips to an average of 56.7°F (13.7°C).Humidity
In Trenton, the average relative humidity in September is 75%.Rainfall
In Trenton, Iowa, in September, it is raining for 11.5 days, with typically 2.56" (65mm) of accumulated precipitation. Throughout the year, there are 140.1 rainfall days, and 29.92" (760mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
In Trenton, the average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:33 am and sunset at 7:38 pm. On the last day of September, in Trenton, sunrise is at 7:02 am and sunset at 6:49 pm CDT.
Sunshine
In Trenton, the average sunshine in September is 9.3h.UV index
In Trenton, the average daily maximum UV index in September 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 ordinary individuals.Note: In September, an average UV index of 4 transforms into the following instructions:
Adopt protective measures - Suggestions to resist sunburn are offered. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Trenton have in September?
What is the UV index reading in September?
Average temperature in September
Trenton, IA
- Average high temperature in September: 76.3°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 (29.7°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).
Average pressure in September
Trenton, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Trenton, IA
- Average wind speed in September: 7.9mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.9mph).
Average humidity in September
Trenton, IA
- Average humidity in September: 75%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Trenton, IA
- Average rainfall in September: 2.56"
The wettest month (with the highest rainfall) is May (4.29").
The driest months (with the least rainfall) are February and December (1.38").
Average rainfall days in September
Trenton, IA
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is February (4.6 days).
Average snowfall in September
Trenton, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.76").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Trenton, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.6 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
Trenton, 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 18min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Trenton, IA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is October (18.4 days).
The month with the least sunshine days is May (10.6 days).
Average UV index in September
Trenton, 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
Trenton, IA
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 56).
The months with the least cloud cover are July, August and September (Cloud cover 31).
Average visibility in September
Trenton, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Trenton, Iowa, USA
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