September weather forecastLondon, TX
September
Weather in September
September, the first month of the autumn in London, is still a tropical month, with an average temperature fluctuating between 86.9°F (30.5°C) and 68.4°F (20.2°C).Temperature
September sees a slight reduction in average high-temperature, with a shift from 94.5°F (34.7°C) in August to a still hot 86.9°F (30.5°C). Throughout the nights in September, London experiences an average low-temperature of 68.4°F (20.2°C).Heat index
In September, the heat index is appraised at a very hot 95°F (35°C). Take additional safety steps, risk of heat exhaustion and heat cramps is notable. Prolonged activity may cause heatstroke.Be aware that heat index ratings are designed for shaded locations and minor breezes. In the presence of direct sunshine, the heat index could be augmented by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', reflects the feeling of heat when considering both air temperature and humidity. This effect is subjective, differing among individuals based on their physical activity and perception of heat, which can be influenced by factors like wind, clothing, and metabolic variances. Understand that direct sun rays can influence the weather's impact, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to children. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Evaporation of sweat is the main factor behind the cooling effect of perspiration in the human body. When there is an excess of moisture in the atmosphere, the efficiency of the evaporation process is lessened, leading to less efficient body cooling and a sensation of overheating. If heat absorption exceeds the body's cooling ability, body temperature can elevate, resulting in potential thermal illnesses.
Humidity
In September, the average relative humidity is 63%.Rainfall
In London, during September, the rain falls for 13.3 days and regularly aggregates up to 1.97" (50mm) of precipitation. In London, during the entire year, the rain falls for 111.3 days and collects up to 17.13" (435mm) of precipitation.Snowfall
March through November are months without snowfall.Daylight
In London, the average length of the day in September is 12h and 20min.On the first day of September, sunrise is at 7:15 am and sunset at 8:00 pm. On the last day of the month, sunrise is at 7:31 am and sunset at 7:24 pm CDT.
Sunshine
The average sunshine in September is 8.7h.UV index
In London, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: The maximum UV index of 6 during September leads to these instructions:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
London, TX
- Average high temperature in September: 86.9°F
The warmest months (with the highest average high temperature) are July and August (94.5°F).
The month with the lowest average high temperature is January (59.4°F).
- Average low temperature in September: 68.4°F
The month with the highest average low temperature is August (73.6°F).
The coldest month (with the lowest average low temperature) is January (40.3°F).
Average pressure in September
London, TX
- Average pressure in September: 29.96"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
London, TX
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is April (12.1mph).
The calmest month (with the lowest average wind speed) is September (8.3mph).
Average humidity in September
London, TX
- Average humidity in September: 63%
The month with the highest relative humidity is May (66%).
The month with the lowest relative humidity is August (53%).
Average rainfall in September
London, TX
- Average rainfall in September: 1.97"
The wettest month (with the highest rainfall) is May (2.52").
The driest month (with the least rainfall) is November (0.63").
Average rainfall days in September
London, TX
- Average rainfall days in September: 13.3 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is January (5.4 days).
Average snowfall in September
London, TX
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.24").
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0").
Average snowfall days in September
London, TX
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
London, TX
- Average daylight in September: 12h and 18min
The month with the longest days is June (Average daylight: 14h and 6min).
The month with the shortest days is December (Average daylight: 10h and 12min).
- Average sunshine in September: 8h and 42min
The month with the most sunshine is July (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
London, TX
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is January (24.6 days).
The month with the least sunshine days is May (14.3 days).
Average UV index in September
London, 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
London, TX
- Average cloud cover in September: 30
The months with the most cloud cover are March and May (Cloud cover 35).
The month with the least cloud cover is August (Cloud cover 19).
Average visibility in September
London, 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).
