September weather forecastIdaho City, ID
September
Weather in September
September brings about the awaited changing of seasons in Idaho City, signaling a departure from summer's heat. The earlier roaring temperatures gradually recede, now ranging from 50.4°F (10.2°C) to 73.9°F (23.3°C). As fall comes knocking, a gentle increase in precipitation occurs, setting the stage for autumn hues. While daylight hours undergo a reduction, the sunlight retains its place for the most part of the day. September's gentle coolness and vivid fall colors serve as cordial invitations to enjoy Idaho's outdoors.Temperature
September's arrival coincides with a drop in the average high-temperature, decreasing from August's 84.7°F (29.3°C) to a still moderately hot 73.9°F (23.3°C). Contrary to the day's heat, an average low-temperature of 50.4°F (10.2°C) is recorded during the nights in September in Idaho City.Humidity
The average relative humidity in September in Idaho City is 41%.Rainfall
In Idaho City, during September, the rain falls for 7.4 days and regularly aggregates up to 0.63" (16mm) of precipitation. Throughout the year, there are 103.4 rainfall days, and 19.84" (504mm) of precipitation is accumulated.Snowfall
July through September are months without snowfall.Daylight
In Idaho City, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 7:07 am and sunset at 8:18 pm. On the last day of September, in Idaho City, sunrise is at 7:40 am and sunset at 7:25 pm MDT.
Sunshine
In September, the average sunshine is 9.4h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for the ordinary person.Note: A daily high UV index of 4 in September leads to these guidelines:
Be vigilant - Suggestions to stave off sun damage are provided. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Boost your sun resistance with garments that are densely woven yet spacious. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Idaho City, ID
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is December (31.3°F).
- Average low temperature in September: 50.4°F
The month with the highest average low temperature is August (56.8°F).
The coldest month (with the lowest average low temperature) is December (19.4°F).
Average pressure in September
Idaho City, ID
- Average pressure in September: 29.95"Hg
The month with the highest atmospheric pressure is January (30.25"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).
Average wind speed in September
Idaho City, ID
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest month (with the lowest average wind speed) is January (4.3mph).
Average humidity in September
Idaho City, ID
- Average humidity in September: 41%
The month with the highest relative humidity is January (85%).
The months with the lowest relative humidity are July and August (33%).
Average rainfall in September
Idaho City, ID
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is March (2.83").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Idaho City, ID
- Average rainfall days in September: 7.4 days
The month with the highest number of rainy days is May (14.2 days).
The month with the least rainy days is January (4.7 days).
Average snowfall in September
Idaho City, ID
- Average snowfall in September: 0"
The month with the highest snowfall is January (20.59").
The months with the least snowfall are July, August and September (0").
Average snowfall days in September
Idaho City, ID
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (14.8 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Idaho City, ID
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 9h and 24min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 12min).
Average sunshine days in September
Idaho City, ID
- Average sunshine days in September: 20.6 days
The month with the most sunshine days is July (22.3 days).
The month with the least sunshine days is March (11.2 days).
Average UV index in September
Idaho City, ID
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in September
Idaho City, ID
- Average cloud cover in September: 15
The month with the most cloud cover is December (Cloud cover 45).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in September
Idaho City, ID
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
