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
As Saint Helena steps into September, the average high-temperature holds at a warm 85.3°F (29.6°C), hinting at a minor fluctuation from the prior month. A stark contrast in day to night temperatures can be seen in September, with an average low-temperature of 54.3°F (12.4°C).Heat index
The heat index value during September is calculated to be a tropical 87.8°F (31°C). Uninterrupted exposure and activity might result in fatigue, potentially causing heat cramps.One should be cognizant that the heat index values are tailored for shaded spots and mild winds. 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 'real feel' or 'apparent temperature', gives an indication of how one might feel in terms of heat after considering humidity. 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. 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 remain especially vital for babies and toddlers. Children frequently do not understand the need for recuperation and hydration. Thirst, being a late manifestation of dehydration, underlines the need to hydrate frequently, especially when engaging in prolonged physical exercises.
Humidity
With an average relative humidity of 53%, September is the least humid month in Saint Helena.Rainfall
In September, the rain falls for 2 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, in Saint Helena, there are 76.2 rainfall days, and 16.93" (430mm) of precipitation is accumulated.Snowfall
January, February, April through December are months without snowfall in Saint Helena.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:39 am and sunset at 7:39 pm. On the last day of September, in Saint Helena, sunrise is at 7:05 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine in Saint Helena, California, is 11h.UV index
In September, the average daily maximum UV index in Saint Helena, California, is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: A maximum daily UV index of 5 during September morphs into the following directions:
Take necessary precautions - Defending against sun damage is advocated. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Frequently asked questions
Is it hot in Saint Helena during September?
What is the least humid month in Saint Helena?
What is the average humidity in September in Saint Helena?
How many days does it rain in September in Saint Helena?
When it does not snow in Saint Helena?
How many hours of daylight does Saint Helena have in September?
What time are sunrise and sunset in September in Saint Helena?
How long on average sun shines in September in Saint Helena?
What is the UV index reading in September in Saint Helena?
Average temperature in September
Saint Helena, CA
- Average high temperature in September: 85.3°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (54.5°F).
- Average low temperature in September: 54.3°F
The month with the highest average low temperature is September (54.3°F).
The coldest month (with the lowest average low temperature) is December (39.6°F).
Average pressure in September
Saint Helena, CA
- Average pressure in September: 29.91"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).
Average wind speed in September
Saint Helena, CA
- Average wind speed in September: 4.6mph
The windiest month (with the highest average wind speed) is May (5.8mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in September
Saint Helena, CA
- Average humidity in September: 53%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (53%).
Average rainfall in September
Saint Helena, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (3.7").
The driest month (with the least rainfall) is July (0").
Average rainfall days in September
Saint Helena, CA
- Average rainfall days in September: 2 days
The month with the highest number of rainy days is March (13.5 days).
The month with the least rainy days is August (0.3 days).
Average snowfall in September
Saint Helena, CA
- Average snowfall in September: 0"
The month with the highest snowfall is March (0.04").
The months with the least snowfall are January, February, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in September
Saint Helena, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is March (0.2 days).
The months with the least snowfall days are January, February, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in September /
Average sunshine in September
Saint Helena, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 11h and 0min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in September
Saint Helena, CA
- Average sunshine days in September: 27.5 days
The month with the most sunshine days is July (30 days).
The month with the least sunshine days is March (15.9 days).
Average UV index in September
Saint Helena, CA
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Saint Helena, CA
- Average cloud cover in September: 10
The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility in September
Saint Helena, CA
- Average visibility in September: 6mi
The months with the highest visibility are February, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and March (5mi).
Saint Helena, California, USA
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