O'Fallon
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O'Fallon Weather in July

July in O'Fallon brings very high temperatures, with highs of 31°C (88°F) and nights dropping to 20°C (68°F). Rainfall is on the higher side this month, averaging around 102 mm (4 in), so keep a rain jacket handy.

Rainfall in O'Fallon in July

Records from the past 30 years suggest around 10 days of rain, with 102 mm (4 in) average for the month. Rainfall intensity is on the higher side this month. Expect more substantial showers rather than light, passing rain.

Temperature in O'Fallon in July

Temperatures in O'Fallon in July top out at 31°C (88°F) and drop to 20°C (68°F) overnight. For most visitors, the main thing to prepare for is the heat during the day. With lows of 20°C (68°F), the nights are warm and generally comfortable. With these average temperatures, expect occasional spikes in warmth. Wear light fabrics and stay cool by hydrating regularly.

Sunshine in O'Fallon in July

There are approximately 311 hours of sunshine this month, resulting in mostly clear days.

Our weather planner can help you find worldwide destinations with pleasant weather during this period. October typically offers the best weather for O'Fallon.

O'Fallon Temperature in July

Min Temperature
20°C (68°F)
Max Temperature
31°C (88°F)
Chance of Rain
33%
Precipitation
102 mm (4 in)
Rainy days
10 days
Humidity
68% *
Sunshine
311 hours *
Percentage Sunshine
68% *
* Data from: St. Louis, the United States of America (25 KM, 15 Miles).

O'Fallon Weather by Month

Pick a month to see the average temperature, rainfall and sunshine in O'Fallon - and find the best time to visit.

Best Places in the United States of America in July

Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in July →

perfect weather
pleasant
tolerable
unpleasant
poor

Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).

What to Wear in O'Fallon in July

Warm but pleasant conditions in O'Fallon in July. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. Expect heavy rainfall, so bring good rain protection and waterproof bags. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in O'Fallon in July

We rated the following activities from 1 (least suitable) to 10 (best) to do.

  • Swimming
    9/10
  • Cycling
    7/10
  • Walking
    7/10
  • Camping
    6/10
  • Outdoor sports
    7/10

O'Fallon 3-Day Forecast

Popular in July

Where to go in July - average daytime high across popular destinations.

Bucket list

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