September weather forecastCaldwell, ID
September
Weather in September
An air of change rustles through Caldwell as September steps in, with autumn beginning its reign subtly. The peak summer heat starts to decline, bringing much-needed relief. While the temperatures continue to remain on the higher side, touching 78.3°F (25.7°C), the nights turn pleasantly cool. The blend of heat during the day and chill at night introduces the perfect weather for a wide range of outdoor activities. September, thus, marks a harmonious meteorological transition.Temperature
Transition into September marks a drop in the average high-temperature, moving from a tropical 89.8°F (32.1°C) in August to a moderately hot 78.3°F (25.7°C). During September, Caldwell's temperature records a considerable difference from its daily highs to an average low of 55.2°F (12.9°C).Humidity
In Caldwell, the average relative humidity in September is 35%.Rainfall
In September, the rain falls for 5.9 days. Throughout September, 0.31" (8mm) of precipitation is accumulated. In Caldwell, during the entire year, the rain falls for 103.7 days and collects up to 9.84" (250mm) of precipitation.Snowfall
In Caldwell, snow does not fall in May through October.Daylight
In Caldwell, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 7:11 am and sunset at 8:21 pm. On the last day of September, sunrise is at 7:44 am and sunset at 7:28 pm MDT.
Sunshine
The average sunshine in September is 9.5h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Undertake protective steps - Recommendations to avoid sunburn are issued. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Caldwell, ID
- Average high temperature in September: 78.3°F
The warmest month (with the highest average high temperature) is July (90.9°F).
The month with the lowest average high temperature is December (36.3°F).
- Average low temperature in September: 55.2°F
The month with the highest average low temperature is August (62.8°F).
The coldest month (with the lowest average low temperature) is December (24.8°F).
Average pressure in September
Caldwell, 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
Caldwell, ID
- Average wind speed in September: 5.4mph
The windiest month (with the highest average wind speed) is April (7.3mph).
The calmest month (with the lowest average wind speed) is January (5.2mph).
Average humidity in September
Caldwell, ID
- Average humidity in September: 35%
The month with the highest relative humidity is January (79%).
The month with the lowest relative humidity is August (29%).
Average rainfall in September
Caldwell, ID
- Average rainfall in September: 0.31"
The wettest month (with the highest rainfall) is March (1.38").
The driest month (with the least rainfall) is July (0.16").
Average rainfall days in September
Caldwell, ID
- Average rainfall days in September: 5.9 days
The month with the highest number of rainy days is March (15.1 days).
The month with the least rainy days is August (3.5 days).
Average snowfall in September
Caldwell, ID
- Average snowfall in September: 0"
The month with the highest snowfall is December (3.35").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Caldwell, ID
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (7.2 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
Caldwell, 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 30min
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 42min).
Average sunshine days in September
Caldwell, ID
- Average sunshine days in September: 21.8 days
The month with the most sunshine days is July (23.3 days).
The month with the least sunshine days is March (14.6 days).
Average UV index in September
Caldwell, ID
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Caldwell, ID
- Average cloud cover in September: 14
The month with the most cloud cover is December (Cloud cover 39).
The months with the least cloud cover are July and August (Cloud cover 8).
Average visibility in September
Caldwell, ID
- 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).
