September weather forecastHayden, ID
September
Weather in September
September marks a change in the warm season with temperatures starting to slide downwards. The rainfall bumps back up slightly to 0.79" (20mm), signaling the onset of the wetter half of the year. The fall equinox in September results in shorter days and extended nights in Hayden a major shift from the surplus daylight of summer. The sudden dip in temperature combined with the onset of more rainfall marks the advent of the fall season. A hint of snowfall re-emerges, hinting at the winter weather just around the corner.Temperature
The onset of September introduces a moderate change in Hayden's weather, with average high-temperatures falling from August's moderately hot 82°F (27.8°C) to an agreeable 71.4°F (21.9°C). Hayden logs a considerable temperature decrease from the daytime highs during the nights in September, with an average reading of 45°F (7.2°C).Humidity
In September, the average relative humidity in Hayden is 58%.Rainfall
In September, in Hayden, the rain falls for 8.4 days. Throughout September, 0.79" (20mm) of precipitation is accumulated. Throughout the year, there are 141.2 rainfall days, and 22.6" (574mm) of precipitation is accumulated.Snowfall
January through May, September through December are months with snowfall. September is the first month it typically snows in Hayden. Throughout September, in the average 0.2 snowfall days, it receives 0.31" (8mm) of snow. In Hayden, during the entire year, snow falls for 71.8 days and aggregates up to 56.54" (1436mm) of snow.Daylight
In September, the average length of the day is 12h and 33min.On the first day of September in Hayden, sunrise is at 6:06 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:27 pm PDT.
Sunshine
The average sunshine in September is 9.8h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: In September, a daily maximum UV index of 4 leads to the following instructions:
Prioritize safety - Recommendations to avert sunburn are shared. To protect against the Sun's most potent rays, avoid direct exposure around midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Hayden, ID
- Average high temperature in September: 71.4°F
The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (31.3°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is August (51.8°F).
The coldest month (with the lowest average low temperature) is December (21.2°F).
Average pressure in September
Hayden, ID
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Hayden, ID
- Average wind speed in September: 4.1mph
The windiest month (with the highest average wind speed) is April (5mph).
The calmest month (with the lowest average wind speed) is December (3.9mph).
Average humidity in September
Hayden, ID
- Average humidity in September: 58%
The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (48%).
Average rainfall in September
Hayden, ID
- Average rainfall in September: 0.79"
The wettest month (with the highest rainfall) is January (3.27").
The driest months (with the least rainfall) are July and August (0.43").
Average rainfall days in September
Hayden, ID
- Average rainfall days in September: 8.4 days
The month with the highest number of rainy days is March (17.5 days).
The month with the least rainy days is August (5.6 days).
Average snowfall in September
Hayden, ID
- Average snowfall in September: 0.31"
The month with the highest snowfall is January (16.57").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Hayden, ID
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (16.9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Hayden, ID
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 9h and 48min
The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).
Average sunshine days in September
Hayden, ID
- Average sunshine days in September: 19.8 days
The month with the most sunshine days is July (23.9 days).
The month with the least sunshine days is February (8.6 days).
Average UV index in September
Hayden, ID
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are February, November and December (UV index 1).
Average cloud cover in September
Hayden, ID
- Average cloud cover in September: 23
The month with the most cloud cover is January (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in September
Hayden, ID
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The month with the lowest visibility is January (3mi).
