September weather forecast
Portales, NM

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Silhouette windmill images on a small hill in Portales in NM, below the colorful yellow, orange, and grey sunset sky
Silhouette windmill images on a small hill in Portales in NM, below the colorful yellow, orange, and grey sunset sky

Weather in September

September in Portales, New Mexico ushers in the initial hints of fall. The month witnesses a temperature shift, on the cooler side, from 61.2°F (16.2°C) to 81.7°F (27.6°C). Although the intensity of the sun reduces, the abundant sunshine helps maintain warm afternoon temperatures. The city experiences the highest rainfall of 1.73" (44mm), signaling the change in seasons. As autumnal hues start to grace the greenery, September is a time of balmy days and crisp nights.

Temperature

Portales, New Mexico, experiences a moderate temperature shift at the start of September, with average high-temperatures adjusting a bit from a tropical 90.1°F (32.3°C) in August to a moderately hot 81.7°F (27.6°C). An average nighttime temperature of 61.2°F (16.2°C) is observed during September.

Heat index

The heat index value for September is appraised at 82.4°F (28°C). Exhaustion becomes probable with enduring exposure and activity, potentially causing heat cramps.
Data suggests that the heat index is set for environments in shade and with a light wind. If exposed to direct sunlight, the heat index could climb by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', binds temperature metrics with humidity values to give a sense of the actual warmth. A person's impression of weather can be shaped by several aspects, among them metabolic variations, pregnancy, and levels of physical activity. One's exposure to direct sunlight has the potential to intensify the heat sensation, increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Younglings are generally more in peril than adults due to their reduced perspiration. Coupled with a larger skin surface relative to their tiny bodies and greater heat production because of their activity, they become more at risk.

Humidity

The average relative humidity in September is 53%.

Rainfall

In September, the rain falls for 12.1 days. Throughout September, 1.73" (44mm) of precipitation is accumulated. In Portales, during the entire year, the rain falls for 86.6 days and collects up to 11.77" (299mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

The average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:18 pm. On the last day of September, sunrise is at 6:47 am and sunset at 6:38 pm MDT.

Sunshine

In Portales, the average sunshine in September is 10.2h.

UV index

In Portales, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.
Note: An average maximum UV index of 5 in September leads to these recommendations:
Act with care - The suggestion to avoid sunburn is emphasized. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Updated: Aug 30, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

During September, Portales experiences an average high-temperature of 81.7°F (27.6°C) and a low-temperature of 61.2°F (16.2°C). In September, the average heat index (a.k.a. 'feels like', 'apparent temperature'), which takes the relative humidity and factors it into the air temperature reading, is appraised at 82.4°F (28°C).

What is the average humidity in September?

In September, the average relative humidity in Portales is 53%.

How much does it rain in September?

In Portales, during September, the rain falls for 12.1 days and regularly aggregates up to 1.73" (44mm) of precipitation.

When it does not snow?

In Portales, snow does not fall in May through September.

Does it snow in September?

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

How many hours of daylight does Portales have in September?

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

When is the sunrise / sunset in September in Portales?

On the first day of September, sunrise is at 6:27 am and sunset at 7:18 pm. On the last day of the month, sunrise is at 6:47 am and sunset at 6:38 pm MDT.

How many hours of sunshine does Portales have in September?

The average sunshine duration in September is 10.2h.

How high is the UV index in September?

In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a medium hazard to health from 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
Portales, NM

Average temperature in September - Portales, NM
  • Average high temperature in September: 81.7°F

The warmest month (with the highest average high temperature) is June (90.7°F).
The month with the lowest average high temperature is December (50°F).

  • Average low temperature in September: 61.2°F

The month with the highest average low temperature is July (69.4°F).
The coldest month (with the lowest average low temperature) is December (31.1°F).

Average pressure in September
Portales, NM

Average pressure in September - Portales, NM
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in September
Portales, NM

Average wind speed in September - Portales, NM
  • Average wind speed in September: 10.6mph

The windiest month (with the highest average wind speed) is April (13.3mph).
The calmest month (with the lowest average wind speed) is August (9.9mph).

Average humidity in September
Portales, NM

Average humidity in September - Portales, NM
  • Average humidity in September: 53%

The month with the highest relative humidity is December (54%).
The month with the lowest relative humidity is April (34%).

Average rainfall in September
Portales, NM

Average rainfall in September - Portales, NM
  • Average rainfall in September: 1.73"

The wettest month (with the highest rainfall) is October (1.81").
The driest month (with the least rainfall) is November (0.28").

Average rainfall days in September
Portales, NM

Average rainfall days in September - Portales, NM
  • Average rainfall days in September: 12.1 days

The month with the highest number of rainy days is July (12.9 days).
The month with the least rainy days is November (2.6 days).

Average snowfall in September
Portales, NM

Average snowfall in September - Portales, NM
  • Average snowfall in September: 0"

The months with the highest snowfall are January and February (1.34").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in September
Portales, NM

Average snowfall days in September - Portales, NM
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is December (3.5 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Portales, NM

Average daylight in September / Average sunshine in September - Portales, NM
  • Average daylight in September: 12h 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 September: 10h and 1min

The month with the most sunshine is June (Average sunshine: 11h and 54min).
The months with the least sunshine are January, February and December (Average sunshine: 7h and 0min).

Average sunshine days in September
Portales, NM

Average sunshine days in September - Portales, NM
  • Average sunshine days in September: 16.2 days

The month with the most sunshine days is January (26.4 days).
The month with the least sunshine days is August (14 days).

Average UV index in September
Portales, NM

Average UV index in September - Portales, NM
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 2).

Average cloud cover in September
Portales, NM

Average cloud cover in September - Portales, NM
  • Average cloud cover in September: 19

The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is June (Cloud cover 13).

Average visibility in September
Portales, NM

Average visibility in September - Portales, NM
  • 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).

Portales, New Mexico, USA

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