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 transition into September subtly indicates a reduction in the average high-temperature, down to a still warm 79.7°F (26.5°C) from August's moderately hot 85.6°F (29.8°C). During September in Derby, Indiana, the average low-temperature is recorded at a moderate 60.1°F (15.6°C).Humidity
The average relative humidity in September in Derby is 74%.Rainfall
The month with the least rainfall in Derby is September, when the rain falls for 11 days and typically collects 0.75" (19mm) of precipitation.Snowfall
In Derby, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 25min.On the first day of September in Derby, sunrise is at 6:16 am and sunset at 7:15 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 6:30 pm CDT.
Sunshine
In September, the average sunshine in Derby is 8.7h.UV index
In September, the average daily maximum UV index in Derby is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: A typical high UV index of 5 in September suggests the following recommendations:
Be vigilant - Preventing sunburn is recommended. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Derby in September?
What is the average humidity in September in Derby?
What is the driest month in Derby?
How many days does it rain in September in Derby?
When it does not snow in Derby?
Does it snow in Derby in September?
What is the average length of the day in September in Derby?
What time are sunrise and sunset in September in Derby?
How long on average sun shines in September in Derby?
What is the UV index reading in September in Derby?
Average temperature in September
Derby, IN
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in September: 60.1°F
The month with the highest average low temperature is July (67.6°F).
The coldest month (with the lowest average low temperature) is January (26.6°F).
Average pressure in September
Derby, IN
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in September
Derby, IN
- Average wind speed in September: 5.6mph
The windiest months (with the highest average wind speed) are January, February and April (8.1mph).
The calmest month (with the lowest average wind speed) is July (5mph).
Average humidity in September
Derby, IN
- Average humidity in September: 74%
The months with the highest relative humidity are February and May (80%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Derby, IN
- Average rainfall in September: 0.75"
The wettest month (with the highest rainfall) is April (2.13").
The driest month (with the least rainfall) is September (0.75").
Average rainfall days in September
Derby, IN
- Average rainfall days in September: 11 days
The month with the highest number of rainy days is May (15.1 days).
The month with the least rainy days is October (8.4 days).
Average snowfall in September
Derby, IN
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.3").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Derby, IN
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (6.1 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
Derby, IN
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is August (Average sunshine: 10h and 30min).
The months with the least sunshine are January and February (Average sunshine: 4h and 18min).
Average sunshine days in September
Derby, IN
- Average sunshine days in September: 16.3 days
The month with the most sunshine days is October (20 days).
The month with the least sunshine days is May (12.5 days).
Average UV index in September
Derby, IN
- 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
Derby, IN
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Derby, IN
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, August, September, October, November and December (6mi).
The months with the lowest visibility are May and July (5mi).
Derby, Indiana, USA
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