Onís, Spain — Weather in September 2026

Climate Overview

Onís, Spain in September has warm conditions, with highs averaging 20.9°C (70°F). Rain falls on about 14 days this month. Sea temperature averages 20.1°C (68°F).

This month falls at the beginning of Autumn.

Daily highs in September gradually drop from around 22°C (71°F) at the start to 20°C (68°F) by month's end.

Rainfall is heaviest during the middle of the month, while the first third tends to be drier.

Expect around 10.4h of sunshine at the start of September, decreasing to 9.3h by the end.

The warmest days tend to fall around the 5th, averaging 22.3°C (72°F).

Compared to August, this month is about 1°C cooler with 3 more rainy days.

Monthly September Averages

Temperature

21°C / 15°C

Feels Like

22°C / 15°C

Rain

14 days · 126 mm

Sunshine

10h / day

Humidity

84% — Very Humid

Wind

15 km/h

Wind Direction

NNE (17°)

Gusts

32 km/h

Daylight

12.5 h

Cloud Cover

61%

Clear Sky Days

2.9

UV Index

5 — Moderate

Sea Temperature

20°C

Dew Point

15°C — Comfortable

Moon Phase

Waxing Crescent · 11%

Climate Charts

Daily averages based on historical data (2016–2025)

Daily Temperature

HighLow

Daily Precipitation

Rainfall

Daily Sunshine

Sunshine

Daily Wind Speed

Wind Speed

Sun Position

Sunrise 08:00

Daylight 12.5h

Sunset 20:33

What to Expect

Daytime temperatures around 21°C (70°F) are ideal for full-day outdoor exploration. Keep afternoons flexible as tropical showers are common — they typically clear within an hour.

Wet weather can spread across much of the day, so it is best to keep outdoor plans flexible.

1 of the last 5 yearly records were warmer than this month's long-run average.

Compare Months

Month	Temp	Feels Like	Rain	Sun	Humidity	UV	Status	Details
January	12°C / 6°C	9°C / 3°C	15days (144 mm) Wet	6.2h Fair	81% Humid	2.1 Moderate	Poor	View Details
February	13°C / 6°C	11°C / 3°C	13days (118 mm) Wet	7.5h Good	81% Humid	2.8 Moderate	Fair	View Details
March	14°C / 7°C	12°C / 4°C	16days (121 mm) Wet	9.3h Good	80% Humid	4.3 Moderate	Fair	View Details
April	15°C / 9°C	14°C / 7°C	14days (105 mm) Wet	10.5h Excellent	81% Humid	5.7 High	Good	View Details
May	17°C / 11°C	18°C / 10°C	15days (104 mm) Wet	11.6h Excellent	83% Humid	6.4 High	Good	View Details
June best	20°C / 15°C	21°C / 14°C	15days (124 mm) Wet	11.4h Excellent	86% Very Muggy	6.3 High	Good	View Details
July best	22°C / 16°C	24°C / 17°C	12days (65 mm) Wet	12.1h Excellent	85% Humid	6.8 High	Excellent	View Details
August best	22°C / 17°C	25°C / 18°C	11days (77 mm) Wet	11.4h Excellent	85% Humid	6.1 High	Excellent	View Details
September best	21°C / 15°C	22°C / 15°C	14days (126 mm) Wet	10h Excellent	84% Humid	5 Moderate	Excellent	View Details
October best	19°C / 13°C	19°C / 12°C	13days (124 mm) Wet	8.3h Good	82% Humid	3.6 Moderate	Good	View Details
November	15°C / 9°C	13°C / 7°C	16days (186 mm) Wet	6.8h Fair	82% Humid	2.2 Moderate	Wet	View Details
December	13°C / 7°C	11°C / 5°C	15days (159 mm) Wet	5.8h Fair	82% Humid	1.8 Low	Poor	View Details

What to Wear

Dress in layers — a mix of long sleeves, light sweaters, and a versatile jacket works best for changeable conditions.

A waterproof jacket or compact umbrella is recommended for occasional showers.

Packing List

UmbrellaWaterproof jacketWaterproof shoesSunscreen (SPF 30+)Sunglasses

Frequently Asked Questions

Expand all

Is September a good time to visit Onís?

September is typically excellent for visiting Onís, with average highs of 21°C (70°F) and around 14 rainy days. Onís, Spain in September has warm conditions, with highs averaging 20.9°C (70°F). Rain falls on about 14 days this month

Does it rain a lot in Onís in September?

Onís typically sees around 14 rainy days in September with 126 mm (5 in) of total rainfall. Pack a waterproof jacket.

Does it get cold at night in Onís in September?

Evenings in Onís during September are mild at 15°C (60°F). A light cardigan is usually enough.

What should I pack for Onís in September?

With highs of 21°C (70°F) and lows of 15°C (60°F) in September, we recommend: Umbrella, Waterproof jacket, Waterproof shoes, Sunscreen (SPF 30+), Sunglasses. Comfortable walking shoes are essential.

Is September among the best months weather-wise in Onís?

Yes, September offers some of the best weather conditions in Onís with comfortable temperatures and lower chances of rain.

What is the UV index in Onís in September?

The average UV index in Onís during September is 5 (moderate). Sunscreen and sunglasses are recommended during midday hours.

How many hours of daylight are there in Onís in September?

Onís gets approximately 13 hours of daylight per day in September, with around 10 hours of sunshine.

Does it snow in Onís in September?

Snow is uncommon in Onís during September based on 10-year climate averages.

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