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
September's presence marks an average high-temperature of a still tropical 86.9°F (30.5°C), subtly varied from August's 90°F (32.2°C). Saint Thomas, during September nights, observes an average temperature of 70.9°F (21.6°C).Heat index
The heat index value for September is appraised at a very hot 102.2°F (39°C). Adopt additional preventive measures, heat cramps and heat exhaustion are potential outcomes. Prolonged activity may trigger heatstroke.Realize that the values for the heat index are set for shaded places and light winds. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', unifies temperature and humidity readings to offer a comprehensive feel of warmth. Depending on the activity and the individual's heat perception, which may vary due to factors including wind, clothing, and metabolic variations, this effect remains subjective. Do note, being directly under sun rays can amplify the heat you feel, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
In the face of high temperatures, the human body's reflex is to perspire, leveraging sweat evaporation for cooling. In the presence of elevated relative humidity, the evaporation rate decreases. This reduction leads to increased body heat retention compared to conditions of dry air. Rising body temperatures resulting from an imbalance in heat absorption can lead to potential thermal issues.
Humidity
The months with the highest humidity are February, July through September and December, with an average relative humidity of 80%.Rainfall
In Saint Thomas, during September, the rain falls for 17.5 days and regularly aggregates up to 2.36" (60mm) of precipitation. In Saint Thomas, during the entire year, the rain falls for 170.8 days and collects up to 30.16" (766mm) of precipitation.Snowfall
In Saint Thomas, snow does not fall in February through November.Daylight
In Saint Thomas, the average length of the day in September is 12h and 20min.On the first day of the month, sunrise is at 6:41 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:50 pm CDT.
Sunshine
In September, the average sunshine is 9.9h.UV index
The average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: A daily high UV index of 6 in September leads to these guidelines:
Stand by precautions and apply sun safety measures. Evading sunburn is of great importance. Attempt to stay under shade and limit exposure to the Sun between 10 a.m. and 4 p.m., when UV radiation is at its peak. Remember, devices such as parasols or canopies might not provide complete sun protection. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in Saint Thomas in September?
What are the most humid months?
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 Saint Thomas have in September?
When is the sunrise / sunset in September in Saint Thomas?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Saint Thomas, LA
- Average high temperature in September: 86.9°F
The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is January (60.1°F).
- Average low temperature in September: 70.9°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 (44.8°F).
Average pressure in September
Saint Thomas, LA
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The months with the lowest atmospheric pressure are June and August (29.96"Hg).
Average wind speed in September
Saint Thomas, LA
- Average wind speed in September: 5.1mph
The windiest months (with the highest average wind speed) are February and April (7.5mph).
The calmest months (with the lowest average wind speed) are July and August (4.8mph).
Average humidity in September
Saint Thomas, LA
- Average humidity in September: 80%
The months with the highest relative humidity are February, July, August, September and December (80%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Saint Thomas, LA
- Average rainfall in September: 2.36"
The wettest month (with the highest rainfall) is July (4.76").
The driest month (with the least rainfall) is November (1.3").
Average rainfall days in September
Saint Thomas, LA
- Average rainfall days in September: 17.5 days
The month with the highest number of rainy days is July (22.3 days).
The month with the least rainy days is November (8.5 days).
Average snowfall in September
Saint Thomas, LA
- Average snowfall in September: 0"
The month with the highest snowfall is January (0.16").
The months with the least snowfall are February, March, April, May, June, July, August, September, October and November (0").
Average snowfall days in September
Saint Thomas, LA
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and December (0.1 days).
The months with the least snowfall days are February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Saint Thomas, LA
- 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: 9h and 5min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).
Average sunshine days in September
Saint Thomas, LA
- Average sunshine days in September: 10.1 days
The month with the most sunshine days is November (20.2 days).
The months with the least sunshine days are July and August (6.4 days).
Average UV index in September
Saint Thomas, LA
- Average UV index in September: 6
The months with the highest UV index are June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in September
Saint Thomas, LA
- Average cloud cover in September: 29
The month with the most cloud cover is December (Cloud cover 47).
The month with the least cloud cover is October (Cloud cover 26).
Average visibility in September
Saint Thomas, LA
- Average visibility in September: 5mi
The months with the highest visibility are January, February, March, April, June, July, August, October, November and December (6mi).
The months with the lowest visibility are May and September (5mi).
Saint Thomas, Louisiana, USA
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