Boulder, United States — Weather in August 2026

Climate Overview

Boulder, United States in August has hot conditions, with highs reaching 29°C (84°F) and afternoons the warmest part of the day. Rain falls on about 13 days this month. Temperatures drop noticeably between day and night.

This month falls at the end of Summer.

Temperatures remain fairly steady throughout August, with daily highs around 29°C (84°F).

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

Expect around 12.5h of sunshine at the start of August, decreasing to 11.7h by the end.

The warmest days tend to fall around the 2th, averaging 29.6°C (85°F).

Compared to July, this month is about 1°C cooler with 3 fewer rainy days. Temperatures begin dropping heading into September.

Monthly August Averages

Temperature

29°C / 14°C

Feels Like

29°C / 13°C

Rain

13 days · 68 mm

Sunshine

12.1h / day

Humidity

55% — Moderate

Wind

13 km/h

Wind Direction

W (264°)

Gusts

31 km/h

Daylight

13.7 h

Cloud Cover

43%

Clear Sky Days

5.7

UV Index

7.6 — Very High

Dew Point

12°C — Comfortable

Moon Phase

Waxing Crescent · 3%

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 06:14

Daylight 13.8h

Sunset 20:00

What to Expect

Daytime temperatures around 29°C (84°F) are ideal for full-day outdoor exploration. Keep afternoons flexible as tropical showers are common — they typically clear within an hour.

Rain usually comes in shorter passing showers rather than all-day rain.

Recent yearly records for August have stayed close to the long-run average.

Compare Months

Month	Temp	Feels Like	Rain	Sun	Humidity	UV	Status	Details
January	4°C / -10°C	1°C / -15°C	6days (28 mm) Good	7.9h Good	68% Muggy	3.2 Moderate	Poor	View Details
February	6°C / -9°C	3°C / -14°C	8days (34 mm) Wet	9.1h Good	64% Muggy	4.4 Moderate	Poor	View Details
March	11°C / -4°C	8°C / -9°C	10days (59 mm) Wet	10.2h Excellent	63% Muggy	5.8 High	Poor	View Details
April	16°C / 0°C	13°C / -4°C	11days (61 mm) Wet	11.2h Excellent	60% Moderate	6.9 High	Poor	View Details
May	20°C / 5°C	18°C / 2°C	17days (122 mm) Wet	12h Excellent	65% Muggy	7.7 Very High	Fair	View Details
June best	27°C / 12°C	27°C / 10°C	14days (78 mm) Wet	13.3h Excellent	57% Moderate	8.1 Very High	Excellent	View Details
July best	30°C / 15°C	30°C / 14°C	16days (70 mm) Wet	13.1h Excellent	55% Moderate	8.3 Very High	Excellent	View Details
August best	29°C / 14°C	29°C / 13°C	13days (68 mm) Wet	12.1h Excellent	55% Moderate	7.6 Very High	Excellent	View Details
September best	27°C / 10°C	25°C / 8°C	9days (43 mm) Wet	11.1h Excellent	53% Moderate	6.5 High	Excellent	View Details
October	19°C / 3°C	16°C / 0°C	7days (36 mm) Good	9.6h Good	55% Moderate	5.1 High	Fair	View Details
November	12°C / -3°C	8°C / -7°C	5days (28 mm) Good	8.3h Good	60% Moderate	3.5 Moderate	Poor	View Details
December	7°C / -7°C	3°C / -11°C	5days (23 mm) Good	7.6h Good	61% Muggy	2.8 Moderate	Poor	View Details

What to Wear

Summer clothing like shorts, t-shirts, and sundresses will be comfortable. Bring a light cardigan for air-conditioned spaces.

Temperatures drop significantly at night, so pack layers you can add or remove throughout the day.

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

Packing List

UmbrellaWaterproof jacketBreathable clothingSunscreen (SPF 30+)Sun hatSunglassesComfortable walking shoes

Frequently Asked Questions

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Is August a good time to visit Boulder?

August is typically excellent for visiting Boulder, with average highs of 29°C (84°F) and around 13 rainy days. Boulder, United States in August has hot conditions, with highs reaching 29°C (84°F) and afternoons the warmest part of

Does it rain a lot in Boulder in August?

Boulder typically sees around 13 rainy days in August with 68 mm (2.7 in) of total rainfall. Pack a waterproof jacket.

Does it get cold at night in Boulder in August?

Evenings in Boulder during August are mild at 14°C (57°F). A light cardigan is usually enough.

What should I pack for Boulder in August?

With highs of 29°C (84°F) and lows of 14°C (57°F) in August, we recommend: Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. Comfortable walking shoes are essential.

Is August among the best months weather-wise in Boulder?

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

What is the UV index in Boulder in August?

The average UV index in Boulder during August is 8 (very high). Strong sun protection is essential — SPF 50+, protective clothing, and avoid prolonged outdoor exposure during peak hours.

How many hours of daylight are there in Boulder in August?

Boulder gets approximately 14 hours of daylight per day in August, with around 12 hours of sunshine.

Does it snow in Boulder in August?

Snow is uncommon in Boulder during August based on 10-year climate averages.

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