September weather forecast
Calais, ME

Share

Weather in September

September sees a transition from summer to autumn, introducing milder weather. Lowering temperatures and slight increase in rainfall marks the beginning of fall weather. The summer heat starts to recede, giving way to the cool, crisp aura of autumn. As daylight hours begin to shrink, the city witnesses spectacular sunset hues earlier each evening. Despite the changes, Calais maintains good weather conditions allowing for continued enjoyment of outdoor activities.

Temperature

Calais in September experiences a gentle temperature dip, with average high-temperatures reducing from a warm 74.3°F (23.5°C) in August to an enjoyable 66.9°F (19.4°C). During September, the average low-temperature is a cool 50.2°F (10.1°C).

Humidity

In September, the average relative humidity in Calais is 79%.

Rainfall

In Calais, in September, during 11.1 rainfall days, 2.13" (54mm) of precipitation is typically accumulated. Throughout the year, there are 155.3 rainfall days, and 32.48" (825mm) of precipitation is accumulated.

Snowfall

In Calais, Maine, snow does not fall in June through September.

Daylight

In September, the average length of the day is 12h and 31min.
On the first day of September, sunrise is at 6:51 am and sunset at 8:06 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:10 pm ADT.

Sunshine

In September, the average sunshine is 7.8h.

UV index

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily high UV index of 4 during September translates into the following recommendations:
Ensure safety - Sun damage prevention is strongly urged. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Updated: Jun 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are September temperatures?

In September, the average high-temperature and low-temperature are 66.9°F (19.4°C) and 50.2°F (10.1°C) respectively.

What is the average humidity in September?

The average relative humidity in September is 79%.

How much does it rain in September?

In Calais, Maine, in September, during 11.1 rainfall days, 2.13" (54mm) of precipitation is typically accumulated.

When it does not snow in Calais?

June through September are months without snowfall.

Does it snow in September?

In Calais, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

The average day length in September is 12h and 31min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:51 am and sunset at 8:06 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:10 pm ADT.

How long on average sun shines in September?

The average sunshine duration in September is 7.8h.

How high is the UV index in September?

In Calais, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Calais, ME

Average temperature in September - Calais, ME
  • Average high temperature in September: 66.9°F

The warmest month (with the highest average high temperature) is July (74.8°F).
The month with the lowest average high temperature is January (26.6°F).

  • Average low temperature in September: 50.2°F

The month with the highest average low temperature is July (56.8°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).

Average pressure in September
Calais, ME

Average pressure in September - Calais, ME
  • Average pressure in September: 30.03"Hg

The month with the highest atmospheric pressure is September (30.03"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Calais, ME

Average wind speed in September - Calais, ME
  • Average wind speed in September: 6.9mph

The windiest month (with the highest average wind speed) is March (9.3mph).
The calmest month (with the lowest average wind speed) is August (6.1mph).

Average humidity in September
Calais, ME

Average humidity in September - Calais, ME
  • Average humidity in September: 79%

The month with the highest relative humidity is February (87%).
The month with the lowest relative humidity is May (78%).

Average rainfall in September
Calais, ME

Average rainfall in September - Calais, ME
  • Average rainfall in September: 2.13"

The wettest month (with the highest rainfall) is December (3.7").
The driest month (with the least rainfall) is August (1.77").

Average rainfall days in September
Calais, ME

Average rainfall days in September - Calais, ME
  • Average rainfall days in September: 11.1 days

The month with the highest number of rainy days is April (17.2 days).
The month with the least rainy days is February (7.8 days).

Average snowfall in September
Calais, ME

Average snowfall in September - Calais, ME
  • Average snowfall in September: 0"

The month with the highest snowfall is January (7.44").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Calais, ME

Average snowfall days in September - Calais, ME
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is January (15.2 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Calais, ME

Average daylight in September / Average sunshine in September - Calais, ME
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in September: 7h and 5min

The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is February (Average sunshine: 3h and 24min).

Average sunshine days in September
Calais, ME

Average sunshine days in September - Calais, ME
  • Average sunshine days in September: 16.6 days

The month with the most sunshine days is September (16.6 days).
The month with the least sunshine days is April (8.5 days).

Average UV index in September
Calais, ME

Average UV index in September - Calais, ME
  • Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in September
Calais, ME

Average cloud cover in September - Calais, ME
  • Average cloud cover in September: 39

The month with the most cloud cover is February (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 38).

Average visibility in September
Calais, ME

Average visibility in September - Calais, ME
  • Average visibility in September: 5mi

The months with the highest visibility are May, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, June, July, August and September (5mi).

Calais, Maine, USA

Weather forecast for your location

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