September weather forecast
Los Altos Hills, CA

Share

Weather in September

The first month of the autumn, September, is still a pleasant month in Los Altos Hills, California, with temperature in the range of an average low of 56.7°F (13.7°C) and an average high of 72.5°F (22.5°C).

Temperature

The beginning of September records an average high-temperature of a still agreeable 72.5°F (22.5°C), almost echoing the conditions of the previous month. During September, the average low-temperature in Los Altos Hills is a mild 56.7°F (13.7°C).

Humidity

The average relative humidity in September is 71%.

Rainfall

In Los Altos Hills, in September, during 2.4 rainfall days, 0.08" (2mm) of precipitation is typically accumulated. Throughout the year, there are 57.5 rainfall days, and 4.76" (121mm) of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:39 am and sunset at 7:36 pm. On the last day of September, in Los Altos Hills, sunrise is at 7:03 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine is 11h.

UV index

June through September, with an average maximum UV index of 5, are months with the highest UV index. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for the average person.
Note: An average UV index of 5 in September transforms into this advice:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
[Resources]

Frequently asked questions

What is the usual temperature for Los Altos Hills in September?

In Los Altos Hills, in September, the average high-temperature is 72.5°F (22.5°C), and the average low-temperature is 56.7°F (13.7°C).

What is the average humidity in September in Los Altos Hills?

In Los Altos Hills, California, the average relative humidity in September is 71%.

How many days does it rain in September in Los Altos Hills?

In September, the rain falls for 2.4 days. Throughout September, 0.08" (2mm) of precipitation is accumulated.

How many hours of daylight does Los Altos Hills have in September?

In September, the average day length in Los Altos Hills, California, is 12h and 25min.

When is the sunrise / sunset in September in Los Altos Hills?

On the first day of September in Los Altos Hills, California, sunrise is at 6:39 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:52 pm PDT.

How many hours of sunshine does Los Altos Hills have in September?

The average sunshine duration in September in Los Altos Hills is 11h.

When is the highest UV index in Los Altos Hills?

The months with the highest UV index in Los Altos Hills are June through September, with an average maximum UV index of 5.

What is the UV index reading in September in Los Altos Hills?

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium hazard to health 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 September
Los Altos Hills, CA

Average temperature in September - Los Altos Hills, CA
  • Average high temperature in September: 72.5°F

The warmest month (with the highest average high temperature) is August (73°F).
The month with the lowest average high temperature is December (55.8°F).

  • Average low temperature in September: 56.7°F

The months with the highest average low temperature are August and September (56.7°F).
The coldest months (with the lowest average low temperature) are January and February (46.4°F).

[Resources]

Average pressure in September
Los Altos Hills, CA

Average pressure in September - Los Altos Hills, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).

[Resources]

Average wind speed in September
Los Altos Hills, CA

Average wind speed in September - Los Altos Hills, CA
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is August (5.5mph).

[Resources]

Average humidity in September
Los Altos Hills, CA

Average humidity in September - Los Altos Hills, CA
  • Average humidity in September: 71%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is October (68%).

[Resources]

Average rainfall in September
Los Altos Hills, CA

Average rainfall in September - Los Altos Hills, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (0.98").
The driest month (with the least rainfall) is June (0.04").

[Resources]

Average rainfall days in September
Los Altos Hills, CA

Average rainfall days in September - Los Altos Hills, CA
  • Average rainfall days in September: 2.4 days

The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is June (0.9 days).

[Resources]

Average daylight in September /
Average sunshine in September
Los Altos Hills, CA

Average daylight in September / Average sunshine in September - Los Altos Hills, CA
  • Average daylight in September: 12h and 2min

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 36min).

  • Average sunshine in September: 11h and 0min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

[Resources]

Average sunshine days in September
Los Altos Hills, CA

Average sunshine days in September - Los Altos Hills, CA
  • Average sunshine days in September: 25.8 days

The months with the most sunshine days are June and July (26.3 days).
The month with the least sunshine days is March (18.3 days).

[Resources]

Average UV index in September
Los Altos Hills, CA

Average UV index in September - Los Altos Hills, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).

[Resources]

Average cloud cover in September
Los Altos Hills, CA

Average cloud cover in September - Los Altos Hills, CA
  • Average cloud cover in September: 12

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).

[Resources]

Average visibility in September
Los Altos Hills, CA

Average visibility in September - Los Altos Hills, 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).

[Resources]

Los Altos Hills, California, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location