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 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
The arrival of September brings an average high-temperature of a still hot 88.2°F (31.2°C), subtly diverging from August's 90.9°F (32.7°C). Nighttime temperature dips to a mean of 72.3°F (22.4°C) during September.Heat index
The heat index value during September is evaluated at an extremely hot 105.8°F (41°C). Incorporate additional safety actions, heat cramps and heat exhaustion are possible. Long-term activity may induce heatstroke.Heat index readings emphasize conditions of light breezes and shaded spots. Exposure to the sun directly might heighten the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is found by incorporating humidity levels into the air temperature measurement. Factors such as metabolic variations, being pregnant, and physical activity can impact an individual's weather perception. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.
When temperatures rise, the human body turns to perspiration, using the cooling power of evaporating sweat. With a lot of moisture in the air, the evaporation process is not as effective, and the body does not cool down as efficiently, creating a perception of overheating. Heat-related disorders may develop if heat gain in the body overshadows its cooling capacity, leading to elevated temperatures.
Humidity
The months with the highest humidity are August and September, with an average relative humidity of 78%.Rainfall
In Keystone Heights, during September, the rain falls for 21.7 days and regularly aggregates up to 3.15" (80mm) of precipitation. In Keystone Heights, during the entire year, the rain falls for 188.6 days and collects up to 33.5" (851mm) of precipitation.Snowfall
In Keystone Heights, Florida, snow does not fall in January through November.Daylight
In Keystone Heights, the average length of the day in September is 12h and 20min.On the first day of the month, sunrise is at 7:05 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:21 am and sunset at 7:14 pm EDT.
Sunshine
The average sunshine in September is 8.5h.UV index
In September, the average daily maximum UV index is 6. A UV Index reading of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for ordinary individuals.Note: A maximum UV index of 6 in September translates into the following recommendations:
Apply measures and align with sun safety principles. Safeguarding against skin and eye injury is pivotal. The time between 10 a.m. and 4 p.m. is when UV radiation is at its peak. Limit exposure to direct sunlight during these hours. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in September?
What is the most humid month?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
How many hours of daylight does Keystone Heights have in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Keystone Heights, FL
- Average high temperature in September: 88.2°F
The warmest month (with the highest average high temperature) is July (91°F).
The month with the lowest average high temperature is January (64.2°F).
- Average low temperature in September: 72.3°F
The month with the highest average low temperature is August (74.8°F).
The coldest month (with the lowest average low temperature) is January (46.6°F).
Average pressure in September
Keystone Heights, FL
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is September (29.97"Hg).
Average wind speed in September
Keystone Heights, FL
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is April (6.3mph).
The calmest month (with the lowest average wind speed) is July (4.5mph).
Average humidity in September
Keystone Heights, FL
- Average humidity in September: 78%
The months with the highest relative humidity are August and September (78%).
The month with the lowest relative humidity is March (71%).
Average rainfall in September
Keystone Heights, FL
- Average rainfall in September: 3.15"
The wettest month (with the highest rainfall) is July (5.31").
The driest months (with the least rainfall) are January and November (1.5").
Average rainfall days in September
Keystone Heights, FL
- Average rainfall days in September: 21.7 days
The month with the highest number of rainy days is August (25.9 days).
The month with the least rainy days is November (9 days).
Average snowfall days in September
Keystone Heights, FL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Keystone Heights, FL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 0min).
The month with the shortest days is December (Average daylight: 10h and 18min).
- Average sunshine in September: 8h and 3min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in September
Keystone Heights, FL
- Average sunshine days in September: 6.9 days
The month with the most sunshine days is January (19.9 days).
The month with the least sunshine days is July (3.6 days).
Average UV index in September
Keystone Heights, FL
- Average UV index in September: 6
The months with the highest UV index are May, June, July and August (UV index 7).
The months with the lowest UV index are January and December (UV index 4).
Average cloud cover in September
Keystone Heights, FL
- Average cloud cover in September: 34
The month with the most cloud cover is December (Cloud cover 40).
The months with the least cloud cover are May and October (Cloud cover 31).
Average visibility in September
Keystone Heights, FL
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October and November (6mi).
The month with the lowest visibility is December (5mi).
Keystone Heights, Florida, USA
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