September weather forecastWatertown, SD
September
Weather in September
September signals the start of Watertown's transition to cooler conditions. A noticeable dip in temperature to a high of 71.6°F (22°C) indicates the early arrival of Fall. Hours of daylight drop to 12.5, paving the way for longer evenings. September's moderate weather encourages outdoor leisure activities like hiking and bird watching as the scenery starts to change hues. The blend of comfortable temperatures and changing colors makes September a delightful month in Watertown.Temperature
Watertown's weather in September involves a mild decrease in the average high-temperature, moving down slightly from August's warm 80.1°F (26.7°C) to an agreeable 71.6°F (22°C). September brings Watertown a consistent average low-temperature of 51.3°F (10.7°C).Humidity
September and October, with an average relative humidity of 68%, are the least humid months.Rainfall
In September, in Watertown, the rain falls for 10.4 days. Throughout September, 1.57" (40mm) of precipitation is accumulated. Throughout the year, in Watertown, there are 112.3 rainfall days, and 18.78" (477mm) of precipitation is accumulated.Snowfall
In Watertown, South Dakota, snow does not fall in June through September.Daylight
In September, the average length of the day in Watertown is 12h and 31min.On the first day of the month, sunrise is at 6:51 am and sunset at 8:04 pm. On the last day of September, in Watertown, sunrise is at 7:26 am and sunset at 7:10 pm CDT.
Sunshine
In Watertown, the average sunshine in September is 8.8h.UV index
In Watertown, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the ordinary person.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat. Beware! Reflection from snow can magnify 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
Watertown, SD
- Average high temperature in September: 71.6°F
The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (19.4°F).
- Average low temperature in September: 51.3°F
The month with the highest average low temperature is July (60.8°F).
The coldest month (with the lowest average low temperature) is January (5.5°F).
Average pressure in September
Watertown, SD
- Average pressure in September: 29.97"Hg
The months with the highest atmospheric pressure are January and February (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Watertown, SD
- Average wind speed in September: 10mph
The windiest month (with the highest average wind speed) is April (11.6mph).
The calmest month (with the lowest average wind speed) is July (8.5mph).
Average humidity in September
Watertown, SD
- Average humidity in September: 68%
The month with the highest relative humidity is January (90%).
The months with the lowest relative humidity are September and October (68%).
Average rainfall in September
Watertown, SD
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is June (3.19").
The driest months (with the least rainfall) are January and February (0.59").
Average rainfall days in September
Watertown, SD
- Average rainfall days in September: 10.4 days
The month with the highest number of rainy days is June (17.2 days).
The month with the least rainy days is February (2.7 days).
Average snowfall in September
Watertown, SD
- Average snowfall in September: 0"
The months with the highest snowfall are January and December (3.74").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Watertown, SD
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (14.4 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Watertown, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Watertown, SD
- Average sunshine days in September: 18.2 days
The month with the most sunshine days is October (19.1 days).
The month with the least sunshine days is June (10.3 days).
Average UV index in September
Watertown, SD
- 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 and December (UV index 1).
Average cloud cover in September
Watertown, SD
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Watertown, SD
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
