September weather forecastMerrill, IA
September
Weather in September
September, the first month of the autumn in Merrill, is also a moderately hot month, with an average temperature varying between 54.9°F (12.7°C) and 75°F (23.9°C).Temperature
Merrill's transition into September involves a gentle shift in temperature, receding from a moderately hot 80.8°F (27.1°C) in August to a still warm 75°F (23.9°C). The average low-temperature during September nights is a cool 54.9°F (12.7°C).Humidity
In Merrill, the average relative humidity in September is 71%.Rainfall
In Merrill, in September, it is raining for 10.6 days, with typically 1.46" (37mm) of accumulated precipitation. In Merrill, Iowa, during the entire year, the rain falls for 112 days and collects up to 15.71" (399mm) of precipitation.Snowfall
In Merrill, snow does not fall in May through September.Daylight
In September, the average length of the day in Merrill is 12h and 29min.On the first day of the month, sunrise is at 6:50 am and sunset at 7:58 pm. On the last day of September, sunrise is at 7:21 am and sunset at 7:07 pm CDT.
Sunshine
The average sunshine in September is 9h.UV index
In Merrill, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The daily high UV index of 4 during September translates into the following recommendations:
Undertake precautions - Obligation exists to protect against skin and eye damage. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Merrill, IA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (25.2°F).
- Average low temperature in September: 54.9°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (12.2°F).
Average pressure in September
Merrill, IA
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Merrill, IA
- Average wind speed in September: 9.1mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.7mph).
Average humidity in September
Merrill, IA
- Average humidity in September: 71%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (66%).
Average rainfall in September
Merrill, IA
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is June (2.48").
The driest month (with the least rainfall) is January (0.35").
Average rainfall days in September
Merrill, IA
- Average rainfall days in September: 10.6 days
The month with the highest number of rainy days is June (16.5 days).
The months with the least rainy days are February and December (2.6 days).
Average snowfall in September
Merrill, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.85").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Merrill, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Merrill, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Merrill, IA
- Average sunshine days in September: 16.8 days
The month with the most sunshine days is November (22.5 days).
The month with the least sunshine days is June (11.9 days).
Average UV index in September
Merrill, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Merrill, IA
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 54).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in September
Merrill, IA
- 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).
