September weather forecastCastroville, TX
September
Weather in September
September, the first month of the autumn in Castroville, is also a hot month, with an average temperature fluctuating between 70.5°F (21.4°C) and 88.5°F (31.4°C).Temperature
The commencement of September includes a gentle temperature shift, with the average high-temperature dropping a bit from a sweltering 95.7°F (35.4°C) in August to a hot 88.5°F (31.4°C). During the month of September, the temperature generally drops to a low average of 70.5°F (21.4°C).Heat index
September's mean heat index is computed to be a sweltering 100.4°F (38°C). More safety actions are required, heat exhaustion and heat cramps are probable. Long-term activity may precipitate heatstroke.It is noted that heat index values are ascertained for locations in the shade and with gentle breezes. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', gives an indication of how one might feel in terms of heat after considering humidity. A person's impression of weather can be affected by numerous aspects, among them metabolic variations, pregnancy, and activity levels. It is important to note that direct sunlight can intensify the weather impact, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Youngsters generally face more threats than adults given their lesser ability to sweat. Coupled with their larger skin surface relative to their small bodies and higher heat production due to their activities, they are more endangered.
Sweat evaporation plays a crucial role in cooling the human body, a process enabled by perspiration. 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. Overheating dangers loom when the body's heat release mechanisms are overshadowed by excessive gain.
Humidity
In September, the average relative humidity is 67%.Rainfall
In Castroville, during September, the rain falls for 14.9 days and regularly aggregates up to 2.83" (72mm) of precipitation. Throughout the year, there are 138.8 rainfall days, and 19.76" (502mm) of precipitation is accumulated.Snowfall
In Castroville, snow does not fall in March through December.Daylight
In Castroville, the average length of the day in September is 12h and 20min.On the first day of September, sunrise is at 7:13 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 7:21 pm CDT.
Sunshine
In September, the average sunshine is 8.3h.UV index
In September, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for the ordinary person.Note: A daily maximum UV index of 6 in September translates into the following instructions:
Uphold preventive measures and conform to sun safety guidelines. Defending against skin and eye harm is crucial. Seek shade and limit direct Sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its peak, but be aware that not all shade structures provide complete sun protection. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Castroville, TX
- Average high temperature in September: 88.5°F
The warmest month (with the highest average high temperature) is August (95.7°F).
The month with the lowest average high temperature is January (61.3°F).
- Average low temperature in September: 70.5°F
The month with the highest average low temperature is August (74.3°F).
The coldest month (with the lowest average low temperature) is January (43.3°F).
Average pressure in September
Castroville, TX
- Average pressure in September: 29.94"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are May and June (29.89"Hg).
Average wind speed in September
Castroville, TX
- Average wind speed in September: 6.6mph
The windiest months (with the highest average wind speed) are April and May (9.1mph).
The calmest month (with the lowest average wind speed) is September (6.6mph).
Average humidity in September
Castroville, TX
- Average humidity in September: 67%
The month with the highest relative humidity is May (73%).
The month with the lowest relative humidity is August (58%).
Average rainfall in September
Castroville, TX
- Average rainfall in September: 2.83"
The wettest month (with the highest rainfall) is May (2.99").
The driest month (with the least rainfall) is February (0.87").
Average rainfall days in September
Castroville, TX
- Average rainfall days in September: 14.9 days
The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is January (8.3 days).
Average snowfall in September
Castroville, TX
- Average snowfall in September: 0"
The month with the highest snowfall is January (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
Castroville, TX
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (0.4 days).
The months with the least snowfall days are March, April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Castroville, TX
- Average daylight in September: 12h and 18min
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 18min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The months with the least sunshine are November and December (Average sunshine: 5h and 18min).
Average sunshine days in September
Castroville, TX
- Average sunshine days in September: 13.1 days
The month with the most sunshine days is January (20.7 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Castroville, TX
- 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
Castroville, TX
- Average cloud cover in September: 35
The months with the most cloud cover are March and May (Cloud cover 47).
The month with the least cloud cover is August (Cloud cover 23).
Average visibility in September
Castroville, TX
- 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).





