September weather forecastSan Martin, CA
September
Weather in September
September, the first month of the autumn in San Martin, is also a moderately hot month, with an average temperature fluctuating between 83.5°F (28.6°C) and 54.5°F (12.5°C).Temperature
The arrival of September marks a slight shift to an average high-temperature of a still warm 83.5°F (28.6°C) from August's 85.8°F (29.9°C). Nightly readings in September display a noticeable downturn from daily highs, with the average low-temperature registering a fresh 54.5°F (12.5°C).Heat index
During September, the heat index is computed to be a hot 86°F (30°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.Data suggests that the heat index is set for environments in shade and with a light wind. 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 'feels like' or 'apparent temperature', is the outcome of merging air's temperature and its humidity metrics. The influence of weather is personal, differing among a variety of individuals based on differences in body mass, stature, and the level of physical activity. Consider the sun's direct rays and their impact; they can potentially increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.
Humidity
July and September, with an average relative humidity of 55%, are the least humid months.Rainfall
In San Martin, during September, the rain falls for 2.7 days and regularly aggregates up to 0.12" (3mm) of precipitation. In San Martin, during the entire year, the rain falls for 70.6 days and collects up to 10.83" (275mm) of precipitation.Daylight
In September, the average length of the day is 12h and 24min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:34 pm. On the last day of September, in San Martin, sunrise is at 7:01 am and sunset at 6:50 pm PDT.
Sunshine
In September, the average sunshine is 11.3h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the average person.Note: A maximum UV index of 5 in September translates into the following recommendations:
Guard yourself - Precautionary measures against sun damage are advocated. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
San Martin, CA
- Average high temperature in September: 83.5°F
The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is December (55.8°F).
- Average low temperature in September: 54.5°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (40.1°F).
Average pressure in September
San Martin, CA
- Average pressure in September: 29.92"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 (29.92"Hg).
Average wind speed in September
San Martin, CA
- Average wind speed in September: 4.2mph
The windiest month (with the highest average wind speed) is May (5.4mph).
The calmest month (with the lowest average wind speed) is November (3.9mph).
Average humidity in September
San Martin, CA
- Average humidity in September: 55%
The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are July and September (55%).
Average rainfall in September
San Martin, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is December (1.97").
The driest months (with the least rainfall) are June, July and August (0.08").
Average rainfall days in September
San Martin, CA
- Average rainfall days in September: 2.7 days
The month with the highest number of rainy days is March (12.4 days).
The month with the least rainy days is August (1 days).
Average daylight in September /
Average sunshine in September
San Martin, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 11h and 18min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
San Martin, CA
- Average sunshine days in September: 26.2 days
The month with the most sunshine days is August (28.7 days).
The month with the least sunshine days is March (16.8 days).
Average UV index in September
San Martin, 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
San Martin, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 5).
Average visibility in September
San Martin, CA
- 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).
