August weather forecast
San Dimas, CA

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Weather in August

August, the last month of the summer in San Dimas, is another tropical month, with an average temperature ranging between max 89.4°F (31.9°C) and min 64.9°F (18.3°C).

Temperature

San Dimas records the warmest temperatures in August, averaging a high of 89.4°F (31.9°C) and a low of 64.9°F (18.3°C).

Heat index

The heat index for August is calculated to be a hot 91.4°F (33°C). Ensure extra safety measures, heat exhaustion and heat cramps are likely. Continuous activity might result in heatstroke.
The metrics for the heat index are tailored for both shady environments and light winds. The heat index could experience an increase of 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'feels like' or 'real feel', is a numerical representation of warmth when taking temperature and moisture levels into account. A person's impression of weather can be shaped by several aspects, among them metabolic variations, pregnancy, and levels of physical activity. Direct sunlight exposure should be noted as it has the potential to increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Children often fail to recognize the requirement to rest and rehydrate. Thirst, being a late symptom of dehydration, underlines the importance of maintaining hydration, especially during ongoing physical activities.

Humidity

August and November, with an average relative humidity of 45%, are the least humid months.

Rainfall

In San Dimas, in August, it is raining for 1.8 days, with typically 0.12" (3mm) of accumulated precipitation. In San Dimas, during the entire year, the rain falls for 45.2 days and collects up to 6.5" (165mm) of precipitation.

Daylight

The average length of the day in August is 13h and 23min.
On the first day of the month, sunrise is at 6:03 am and sunset at 7:51 pm. On the last day of August, sunrise is at 6:24 am and sunset at 7:17 pm PDT.

Sunshine

The average sunshine in August is 12h.

UV index

The months with the highest UV index are July and August, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for the average person.
Note: In August, a daily UV index of 7 turns into the following recommendations:
Eschew overexposure. Those with light skin may suffer burns in fewer than 20 minutes. From 10 a.m. to 4 p.m., when UV radiation is at its strongest, limit direct exposure to the Sun and note that shade structures may not provide full sun protection. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Updated: Aug 29, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the warmest month?

August temperatures tend to peak at an average high of 89.4°F (31.9°C) and dip to a low of 64.9°F (18.3°C).

How hot does it get in August?

The high-temperature, in August, in San Dimas, records 89.4°F (31.9°C), while the low-temperature is 64.9°F (18.3°C). The average heat index (a.k.a. 'real feel', 'feels like'), which calculates the temperature value influenced by the moisture in the air, in August is calculated to be 91.4°F (33°C).

What are the least humid months?

August and November, with an average relative humidity of 45%, are the least humid months.

What is the average humidity in August?

In San Dimas, the average relative humidity in August is 45%.

How much does it rain in August?

In San Dimas, in August, during 1.8 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

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

In August, the average day length in San Dimas is 13h and 23min.

What time are sunrise and sunset in August?

On the first day of August, sunrise is at 6:03 am and sunset at 7:51 pm. On the last day of the month, sunrise is at 6:24 am and sunset at 7:17 pm PDT.

How long on average sun shines in August?

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

What are the months with the highest UV index?

The months with the highest UV index are July and August, with an average maximum UV index of 7.

What is the UV index reading in August?

In August, the average daily maximum UV index is 7. A UV Index reading of 6 to 7 represents a high health vulnerability from exposure to Sun's UV rays.
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 Dimas, CA

Average temperature in August - San Dimas, CA
  • Average high temperature in August: 89.4°F

The warmest month (with the highest average high temperature) is August (89.4°F).
The month with the lowest average high temperature is December (62.4°F).

  • Average low temperature in August: 64.9°F

The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

Average pressure in August
San Dimas, CA

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

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in August
San Dimas, CA

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

The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.3mph).

Average humidity in August
San Dimas, CA

Average humidity in August - San Dimas, CA
  • Average humidity in August: 45%

The months with the highest relative humidity are March and May (55%).
The months with the lowest relative humidity are August and November (45%).

Average rainfall in August
San Dimas, CA

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

The wettest month (with the highest rainfall) is February (1.46").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in August
San Dimas, CA

Average rainfall days in August - San Dimas, CA
  • Average rainfall days in August: 1.8 days

The month with the highest number of rainy days is March (6.3 days).
The month with the least rainy days is June (1.2 days).

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

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

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in August: 12h and 0min

The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 7h and 0min).

Average sunshine days in August
San Dimas, CA

Average sunshine days in August - San Dimas, CA
  • Average sunshine days in August: 26.9 days

The month with the most sunshine days is June (27.8 days).
The month with the least sunshine days is February (22 days).

Average UV index in August
San Dimas, CA

Average UV index in August - San Dimas, CA
  • Average UV index in August: 7

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in August
San Dimas, CA

Average cloud cover in August - San Dimas, CA
  • Average cloud cover in August: 5

The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in August
San Dimas, CA

Average visibility in August - San Dimas, 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).

San Dimas, California, USA

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