When to go · O'Fallon, Illinois
O'Fallon, Illinois in December
Avoid month. Listed as a month to avoid: Jul–Aug (humid), Dec–Feb (cold).
Key facts
- Verdict
- Avoid
- Temperature
- 6°C (43°F)43°F (6°C) / −4°C (25°F)25°F (−4°C)
- average high / low
- Rain days
- 9
- Crowds
- High
- United States overall
- Prices
- High
- United States overall
Verdict
Listed as a month to avoid: Jul–Aug (humid), Dec–Feb (cold).
Is another month better than December?
December is rated avoid. These months rate higher:
Weather in December
- O'Fallon, IllinoisHighs around 6 °C (43 °F), lows around -4 °C (25 °F), rain on about 9 daysHighs around 43 °F (6 °C), lows around 25 °F (-4 °C), rain on about 9 days
Festivals and holidays
Dates as our data lists them. Moving holidays (lunar and Islamic calendars, Easter) shift every year: check the date for your year before you build a trip on it.
Christmas Day big impact
25 Dec · United States
Most businesses closed; flights full from about 20 Dec to 2 Jan.
Crowds and prices
- Crowds · United States overall
- High
- Prices · United States overall
- High
United States overall: Holiday lights in New York, ski season opens; flights and hotels peak around Christmas and New Year.
High-price month: see what to book ahead.
Compare two months
Weather, crowds and prices for any two months in O'Fallon, Illinois, side by side.
Verdict
Dec: Avoid
Apr: Great (better)
Daytime high
Dec: 6 °C (43 °F)43 °F (6 °C)
Apr: 20 °C (68 °F)68 °F (20 °C)
Night low
Dec: -4 °C (25 °F)25 °F (-4 °C)
Apr: 7 °C (45 °F)45 °F (7 °C)
Rain days
Dec: 9 (better)
Apr: 11
Crowds
Dec: High
Apr: Medium
Prices
Dec: High
Apr: Medium
Festivals listed
Dec: 1
Apr: 1
December: Listed as a month to avoid: Jul–Aug (humid), Dec–Feb (cold).
April: Inside O'Fallon, Illinois's best window: Apr–Jun, Sep–Oct.
O'Fallon, Illinois: figures are long-term averages from this guide, not a forecast.
What to pack
- A warm coat, hat and gloves for mornings and evenings