September weather forecast
Carlsbad, CA

Share
The skyline and clear coastline of Carlsbad in California
The skyline and clear coastline of Carlsbad in California

Weather in September

Navigating from summer, September in Carlsbad begins to cool slightly. With fewer daylight hours, clearer skies, and stability in wind speeds, the outdoor charm persists. The drop in sea temperature subtly marks the transition from summer to fall. Although daylight hours reduce, the city maintains its warm, vibrant aura. Remarkably, sea temperatures stay consistently warm at 66.9°F (19.4°C) indicating an extension of summer activities.

Temperature

Carlsbad experiences a recorded average high-temperature of a still warm 77.9°F (25.5°C) in September, closely aligned with August's 78.6°F (25.9°C). Carlsbad, during the nights of September, experiences an average temperature drop to a comfortable 63.5°F (17.5°C).

Humidity

In Carlsbad, the average relative humidity in September is 67%.

Rainfall

In Carlsbad, in September, during 4.9 rainfall days, 0.31" (8mm) of precipitation is typically accumulated. In Carlsbad, California, during the entire year, the rain falls for 68.2 days and collects up to 9.49" (241mm) of precipitation.

Ocean temperature

In Carlsbad, California, the average seawater temperature in September is 66.9°F (19.4°C).
Note: For most people, swimming in water at 66.9°F (19.4°C) is not a pleasurable experience. Breathing control gets harder as the water temperature descends from 69.8°F (21°C) to 59°F (15°C).

Daylight

The average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:24 am and sunset at 7:13 pm. On the last day of September, in Carlsbad, sunrise is at 6:43 am and sunset at 6:34 pm PDT.

Sunshine

In September, the average sunshine in Carlsbad is 10.5h.

UV index

July through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, the maximum UV index of 6 suggests this advice:
Resist overexposure. Safeguarding from solar damage is indispensable. UV radiation from the Sun is most intense between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
[Resources]

Frequently asked questions

What is the temperature in September in Carlsbad?

During September, Carlsbad experiences an average high-temperature of 77.9°F (25.5°C) and a low-temperature of 63.5°F (17.5°C).

What is the average humidity in September in Carlsbad?

In September, the average relative humidity in Carlsbad, California, is 67%.

How many days does it rain in September in Carlsbad?

In Carlsbad, during September, the rain falls for 4.9 days and regularly aggregates up to 0.31" (8mm) of precipitation.

What is the ocean temperature in September in Carlsbad?

In Carlsbad, the average seawater temperature in September is 66.9°F (19.4°C). For swimming, a surface water temperature of 66.9°F (19.4°C) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 69.8°F (21°C).

What is the average length of the day in September in Carlsbad?

The average day length in September in Carlsbad is 12h and 22min.

When is the sunrise / sunset in September in Carlsbad?

On the first day of September in Carlsbad, California, sunrise is at 6:24 am and sunset at 7:13 pm. On the last day of the month, sunrise is at 6:43 am and sunset at 6:34 pm PDT.

How long on average sun shines in September in Carlsbad?

The average sunshine duration in September is 10.5h.

What is the month with the highest UV index in Carlsbad?

The months with the highest UV index in Carlsbad, California, are July through September, with an average maximum UV index of 6.

What is the UV index reading in September in Carlsbad?

In Carlsbad, the average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health threat 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
Carlsbad, CA

Average temperature in September - Carlsbad, CA
  • Average high temperature in September: 77.9°F

The warmest month (with the highest average high temperature) is August (78.6°F).
The month with the lowest average high temperature is December (62.4°F).

  • Average low temperature in September: 63.5°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 (49.6°F).

[Resources]

Average pressure in September
Carlsbad, CA

Average pressure in September - Carlsbad, CA
  • Average pressure in September: 29.88"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are June and September (29.88"Hg).

[Resources]

Average wind speed in September
Carlsbad, CA

Average wind speed in September - Carlsbad, CA
  • Average wind speed in September: 5mph

The windiest months (with the highest average wind speed) are April and May (6mph).
The calmest month (with the lowest average wind speed) is October (4.8mph).

[Resources]

Average humidity in September
Carlsbad, CA

Average humidity in September - Carlsbad, CA
  • Average humidity in September: 67%

The month with the highest relative humidity is June (73%).
The month with the lowest relative humidity is November (60%).

[Resources]

Average rainfall in September
Carlsbad, CA

Average rainfall in September - Carlsbad, CA
  • Average rainfall in September: 0.31"

The wettest month (with the highest rainfall) is December (1.97").
The driest month (with the least rainfall) is June (0.12").

[Resources]

Average rainfall days in September
Carlsbad, CA

Average rainfall days in September - Carlsbad, CA
  • Average rainfall days in September: 4.9 days

The month with the highest number of rainy days is March (8 days).
The month with the least rainy days is June (2.7 days).

[Resources]

Average sea temperature in September
Carlsbad, CA

Average sea temperature in September - Carlsbad, CA
  • Average sea temperature in September: 66.9°F

The best month for swimming (with the highest average sea temperature) is August (68°F).
The coldest months (with the lowest average sea temperature) are January and February (58.7°F).

[Resources]

Average daylight in September /
Average sunshine in September
Carlsbad, CA

Average daylight in September / Average sunshine in September - Carlsbad, CA
  • Average daylight in September: 12h 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 September: 10h and 3min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 6h and 36min).

[Resources]

Average sunshine days in September
Carlsbad, CA

Average sunshine days in September - Carlsbad, CA
  • Average sunshine days in September: 22.4 days

The month with the most sunshine days is October (24.2 days).
The month with the least sunshine days is February (20 days).

[Resources]

Average UV index in September
Carlsbad, CA

Average UV index in September - Carlsbad, CA
  • Average UV index in September: 6

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

[Resources]

Average cloud cover in September
Carlsbad, CA

Average cloud cover in September - Carlsbad, CA
  • Average cloud cover in September: 12

The month with the most cloud cover is December (Cloud cover 25).
The month with the least cloud cover is August (Cloud cover 8).

[Resources]

Average visibility in September
Carlsbad, CA

Average visibility in September - Carlsbad, 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]

Carlsbad, California, USA

Weather forecast for your location

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