St. Louis in August

In August, St. Louis averages 30°C (85°F) during the day and 20°C (69°F) at night, with frequent rain — about 18 days of the month see precipitation (140 mm total).

Shoulder

Conditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.

It's peak hurricane season in St. Louis during August. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.

30°C
Avg high
20°C
Avg low
18
Rain days
140 mm
Rainfall

How August compares to the rest of the year in St. Louis

3rd
warmest month of the 12
2nd
wettest month of the 12
10%
of yearly rainfall falls in August
13 h 41 min
daylight on the 15th

August is one of the warmest months in St. Louis (3rd of 12) and one of the wettest months (2nd of 12). Daytime temperature runs 11°C above the annual average (19°C). August runs 1°C cooler than July (31°C) and cools 2°C in September (27°C).

August sunrise & sunset in St. Louis

🌅
Sunrise (15th)
6:14 AM
🌇
Sunset (15th)
7:55 PM
Day length
13 h 41 min

Times shown for St. Louis local time (America/Chicago), calculated for the 15th of August. They shift by a few minutes day to day across the month.

Photography light in St. Louis — August

Golden-hour and blue-hour windows for the 15th of August, in St. Louis's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).

🌅 Blue hour (AM)
5:14 AM – 5:54 AM
🌄 Golden hour (AM)
5:54 AM – 6:54 AM
🌇 Golden hour (PM)
7:15 PM – 8:15 PM
🌆 Blue hour (PM)
8:15 PM – 8:55 PM
Milky Way galactic core
Fair
Core only briefly above the horizon — a marginal month even from dark sites near St. Louis.

📅 When to book — St. Louis in August

Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on August's tier (Shoulder) and St. Louis's popularity.

✈ Flights — lead time
6-10 weeks
Sweet spot for value. Major fare-sales (US: Black Friday, EU: post-Easter) hit hardest in shoulder months for shoulder travel. ⚠ Peak hazard season — book flexible-change tickets and travel insurance with weather-disruption coverage.
🏨 Lodging — lead time
4-8 weeks
Lots of selection. Look for shoulder-season packages — many hotels add value (free breakfast, spa credit) to fill rooms.

Crowds & pricing — August in St. Louis

Shoulder

St. Louis is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.

Why this tier: Northern Hemisphere summer holidays peak hazard season (1 active)

Sun & mosquito risk — August in St. Louis

☀️ UV Index (noon, 15th)
11.4
Extreme
Stay indoors during midday hours; SPF 50+ even briefly outside, UPF clothing, wide-brim hat, sunglasses essential.
🦟 Mosquito risk
●●●●●
Severe
Severe mosquito season with active disease transmission risk. DEET 30%+, picaridin 20%, long sleeves day and night, treated nets, and check CDC/WHO travel advisories before going.

UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.

St. Louis in other months

MonthAvg highAvg lowRainfallRain daysSnow days
January 5°C / 41°F -4°C / 25°F 74 mm 13
February 7°C / 45°F -4°C / 26°F 72 mm 13
March 13°C / 56°F 3°C / 37°F 133 mm 16
April 19°C / 66°F 8°C / 46°F 132 mm 16
May 25°C / 76°F 14°C / 58°F 130 mm 20
June 30°C / 86°F 20°C / 67°F 137 mm 17
July 31°C / 87°F 21°C / 70°F 152 mm 17
August 30°C / 85°F 20°C / 69°F 140 mm 18
September 27°C / 81°F 17°C / 63°F 112 mm 13
October 20°C / 68°F 10°C / 51°F 106 mm 14
November 12°C / 54°F 3°C / 37°F 77 mm 12
December 8°C / 46°F -1°C / 31°F 76 mm 10

Other cities with similar August weather

🌍 See the full ranked list of climate twins for St. Louis in August →

Frequently asked questions

How hot is St. Louis in August?

In August, St. Louis averages a high of 30°C (85°F) and a low of 20°C (69°F) — generally hot.

Does it rain a lot in St. Louis in August?

August is quite rainy in St. Louis, with about 18 rainy days on average.

Is August a good time to visit St. Louis?

August is hot but on the rainy side. It suits travelers who are comfortable with hot weather; check the month-by-month ranking to compare it against the rest of the year.

What should I pack for St. Louis in August?

Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full August packing list for St. Louis for a complete, climate-based checklist.

Open St. Louis on the interactive map

Check the live 10-day forecast and sunrise/sunset.