August weather forecast
San Marcos, CA

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Weather in August

The last month of the summer, August, is another warm month in San Marcos, California, with an average temperature fluctuating between 64.2°F (17.9°C) and 81.9°F (27.7°C).

Temperature

The warmest period is August, when temperatures fluctuate between an average high of 81.9°F (27.7°C) and a low of 64.2°F (17.9°C).

Heat index

For most parts of August, the heat index is computed to be 84.2°F (29°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Be informed that the heat index values are oriented around shady conditions and gentle breezes. Heat index values may surge by up to 15 Fahrenheit (8 Celsius) degrees in the presence of direct sunlight.
Note: The heat index, also known as 'feels like' or 'felt air temperature', blends air temperature and moisture content to represent the felt temperature to humans. 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. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.

Humidity

The average relative humidity in August in San Marcos is 63%.

Rainfall

In San Marcos, California, in August, during 1.6 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. In San Marcos, during the entire year, the rain falls for 52.1 days and collects up to 6.1" (155mm) of precipitation.

Daylight

In August, the average length of the day is 13h and 20min.
On the first day of the month, sunrise is at 6:02 am and sunset at 7:47 pm. On the last day of August, in San Marcos, sunrise is at 6:22 am and sunset at 7:14 pm PDT.

Sunshine

In August, the average sunshine is 12h.

UV index

June through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for the ordinary person.
Note: In August, a regular UV index of 6 translates into these guidelines:
Exercise precautions and adapt sun safety practices. Defence against skin and eye affliction is paramount. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.
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Frequently asked questions

What is the warmest month in San Marcos?

San Marcos's warmest weather arrives in August, when temperatures average a high of 81.9°F (27.7°C) and a low of 64.2°F (17.9°C).

What is the usual temperature for San Marcos in August?

The high-temperature, in August, in San Marcos, records 81.9°F (27.7°C), while the low-temperature is 64.2°F (17.9°C). In August, the average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines air temperature and relative humidity, is computed to be 84.2°F (29°C).

What is the average humidity in August in San Marcos?

The average relative humidity in August in San Marcos, California, is 63%.

How much does it rain in San Marcos in August?

In August, in San Marcos, California, the rain falls for 1.6 days. Throughout August, 0.12" (3mm) of precipitation is accumulated.

How many hours of daylight does San Marcos have in August?

The average day length in August in San Marcos, California, is 13h and 20min.

When are sunrise and sunset in August in San Marcos?

On the first day of August in San Marcos, sunrise is at 6:02 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 6:22 am and sunset at 7:14 pm PDT.

How long on average sun shines in August in San Marcos?

In August, the average sunshine duration in San Marcos is 12h.

When is the highest UV index in San Marcos?

June through September, with an average maximum UV index of 6, are months with the highest UV index in San Marcos.

What is the UV index reading in August in San Marcos?

In San Marcos, California, the average daily maximum UV index in August is 6. A UV Index estimate of 6 to 7 represents a high health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
San Marcos, CA

Average temperature in August - San Marcos, CA
  • Average high temperature in August: 81.9°F

The warmest month (with the highest average high temperature) is August (81.9°F).
The months with the lowest average high temperature are February and December (63.3°F).

  • Average low temperature in August: 64.2°F

The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is February (48°F).

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Average pressure in August
San Marcos, CA

Average pressure in August - San Marcos, CA
  • Average pressure in August: 29.88"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

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Average wind speed in August
San Marcos, CA

Average wind speed in August - San Marcos, CA
  • Average wind speed in August: 4.7mph

The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is October (4.4mph).

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Average humidity in August
San Marcos, CA

Average humidity in August - San Marcos, CA
  • Average humidity in August: 63%

The month with the highest relative humidity is May (70%).
The month with the lowest relative humidity is November (56%).

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Average rainfall in August
San Marcos, CA

Average rainfall in August - San Marcos, CA
  • Average rainfall in August: 0.12"

The wettest month (with the highest rainfall) is December (1.22").
The driest month (with the least rainfall) is June (0.08").

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Average rainfall days in August
San Marcos, CA

Average rainfall days in August - San Marcos, CA
  • Average rainfall days in August: 1.6 days

The month with the highest number of rainy days is March (7.8 days).
The month with the least rainy days is June (1.2 days).

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Average daylight in August /
Average sunshine in August
San Marcos, CA

Average daylight in August / Average sunshine in August - San Marcos, CA
  • Average daylight in August: 13h and 2min

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in August: 12h and 0min

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 48min).

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Average sunshine days in August
San Marcos, CA

Average sunshine days in August - San Marcos, CA
  • Average sunshine days in August: 25.8 days

The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is February (20 days).

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Average UV index in August
San Marcos, CA

Average UV index in August - San Marcos, CA
  • Average UV index in August: 6

The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).

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Average cloud cover in August
San Marcos, CA

Average cloud cover in August - San Marcos, CA
  • Average cloud cover in August: 7

The months with the most cloud cover are March and December (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 7).

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Average visibility in August
San Marcos, CA

Average visibility in August - San Marcos, CA
  • Average visibility in August: 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).

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San Marcos, California, USA

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