Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
During September, Williams observes a subtle ascent to a warm 85.6°F (29.8°C) from August's 90.5°F (32.5°C) in the average high-temperature. During the nights in September, Williams observes an average low-temperature of 68.5°F (20.3°C).Heat index
For September, the heat index is appraised at a sweltering 96.8°F (36°C). Heightened precautions are necessary, heat cramps and heat exhaustion are potential risks. Continuous activity could lead to heatstroke.Research indicates the heat index considers values in shaded locales and with light winds. Direct sunlight has the potential to heighten heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', provides an understanding of perceived warmth by combining temperature and relative humidity. This effect tends to be personal, with the weather perception differing among individuals due to variations in body mass, height, and exertion. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Children often fail to understand the importance of rest and rehydration. Thirst is a late manifestation of dehydration - hence, it is crucial to stay hydrated, especially during ongoing physical activities.
To offset high temperatures, the human body releases sweat which, upon evaporation, cools it down. In conditions of both high temperature and humidity (a high heat index), sweating is limited and the perception of heat is enhanced. Heat absorption that surpasses the body's shedding capability can lead to overheating and varying levels of dehydration.
Humidity
The average relative humidity in September in Williams is 76%.Rainfall
In Williams, in September, it is raining for 14.2 days, with typically 1.89" (48mm) of accumulated precipitation. Throughout the year, there are 149.7 rainfall days, and 21.5" (546mm) of precipitation is accumulated.Snowfall
March through December are months without snowfall.Daylight
The average length of the day in September is 12h and 22min.On the first day of September, sunrise is at 6:58 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:17 am and sunset at 7:08 pm EDT.
Sunshine
The average sunshine in September in Williams, South Carolina, is 8.7h.UV index
In September, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: An average maximum UV index of 6 in September leads to these recommendations:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is most intense, and remember that not all shade structures provide full protection. During bright days, sunglasses that offer UVA and UVB defense are recommended.
Frequently asked questions
How hot does it get in Williams in September?
What is the average humidity in September in Williams?
How many days does it rain in September in Williams?
When it does not snow in Williams?
How many hours of daylight does Williams have in September?
When are sunrise and sunset in September in Williams?
How many hours of sunshine does Williams have in September?
How high is the UV index in September in Williams?
Average temperature in September
Williams, SC
- Average high temperature in September: 85.6°F
The warmest month (with the highest average high temperature) is July (91.8°F).
The month with the lowest average high temperature is January (56.1°F).
- Average low temperature in September: 68.5°F
The month with the highest average low temperature is July (73.4°F).
The coldest month (with the lowest average low temperature) is January (39.9°F).
Average pressure in September
Williams, SC
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.97"Hg).
Average wind speed in September
Williams, SC
- Average wind speed in September: 5.3mph
The windiest month (with the highest average wind speed) is April (6.7mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Williams, SC
- Average humidity in September: 76%
The months with the highest relative humidity are August and December (77%).
The months with the lowest relative humidity are January, March and November (72%).
Average rainfall in September
Williams, SC
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is August (3.15").
The driest month (with the least rainfall) is November (0.75").
Average rainfall days in September
Williams, SC
- Average rainfall days in September: 14.2 days
The month with the highest number of rainy days is July (21.1 days).
The month with the least rainy days is November (6.2 days).
Average snowfall in September
Williams, SC
- Average snowfall in September: 0"
The months with the highest snowfall are January and February (0.12").
The months with the least snowfall are March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in September
Williams, SC
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (0.4 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Williams, SC
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in September
Williams, SC
- Average sunshine days in September: 13.5 days
The month with the most sunshine days is November (21.1 days).
The month with the least sunshine days is July (6.9 days).
Average UV index in September
Williams, SC
- Average UV index in September: 6
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January and December (UV index 3).
Average cloud cover in September
Williams, SC
- Average cloud cover in September: 31
The month with the most cloud cover is December (Cloud cover 42).
The months with the least cloud cover are July and October (Cloud cover 29).
Average visibility in September
Williams, SC
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Williams, South Carolina, USA
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