O'Fallon, Illinois, United States of America: What to pack, what to wear, and when to go [2018]

Traveling to O'Fallon, Illinois, United States of America? If you're planning to go to O'Fallon, here is some important information about when to go, what to wear, and what to pack:

When to go to O'Fallon, Illinois, United States of America

Based on the climate and weather in O'Fallon, the best time to go is September. See below for details.

What to wear/what to pack for O'Fallon, Illinois, United States of America by month

January

If you are traveling to O'Fallon in January, you will notice that it can be very chilly. Expect it to rain about a third of the time and snow sometimes.

Daytime temperatures are in the high 30s F (single digits C).

What to wear/what to pack:

  • Rain coat
  • Waterproof footwear
  • Gloves or mittens
  • Heavy socks
  • Waterproof luggage
  • Cold weather footwear
  • Heavy jacket
  • Umbrella
  • Warm pants or jeans
  • Sweaters

February

February is cold. Temperatures average in the 40s F (single digits C) during the day. It rains about a third of the time.

What to wear/what to pack:

  • Heavy socks
  • Rain coat
  • Waterproof footwear
  • Waterproof luggage
  • Cold weather footwear
  • Heavy jacket
  • Gloves or mittens
  • Sweaters
  • Umbrella
  • Warm pants or jeans

March

March in O'Fallon is crisp and somewhat rainy. The rain can amount to several inches/centimeters.

During this time, temperatures average in the 50s F (low 10s C), although night temperatures can dip into the low 20s F (single digits below 0 C).

What to wear/what to pack:

  • Waterproof luggage that you don't mind ruining
  • Socks
  • Fleeces
  • Light gloves or mittens
  • Rain coat
  • Warm pants or jeans
  • Umbrella
  • Rain boots
  • Standard footwear
  • Jacket or coat

April

April in O'Fallon is mild and somewhat rainy. The rain can amount to several inches/centimeters.

During this time, temperatures average in the high 60s F (high 10s C), although night temperatures can dip into the low 40s F (single digits C).

What to wear/what to pack:

  • Rain boots
  • Rain coat
  • Pants or jeans
  • Light jacket or fleece
  • Standard footwear
  • Umbrella
  • Long skirts
  • Socks
  • Long sleeve shirts or blouses
  • Dresses
  • Waterproof luggage that you don't mind ruining

May

May is warm and somewhat rainy. Temperatures average in the 70s F (mid 20s C) during the day. It rains a bit less than half of the time.

What to wear/what to pack:

  • Umbrella
  • Sunscreen lotion
  • Rain boots
  • Long and short sleeve shirts
  • Skirts
  • Waterproof luggage that you don't mind ruining
  • Rain coat
  • Shorts or short pants
  • Sandals
  • Dresses
  • Light footwear

June

If you visit O'Fallon during June, you are likely to find that it is pretty consistently hot. Temperatures tend to hover around the 80s F (high 20s C) during the day, while at night they can dip into the low 60s F (high 10s C).

Humidity is generally between 50 and 60% during the day. In terms of precipitation, you can expect it to rain about a third of the time.

What to wear/what to pack:

  • Skirts
  • Waterproof luggage that you don't mind ruining
  • Dresses
  • Rain boots
  • Umbrella
  • Sandals
  • Rain coat
  • Short sleeve shirts
  • Sunscreen lotion
  • Shorts
  • Sunglasses

July

July in this region is extremely hot. Temperatures average in the high 80s F (low 30s C) during the day. It rains 5-10 days this month.

What to wear/what to pack:

  • Umbrella
  • Shorts
  • Sunglasses
  • Sunscreen lotion
  • Short sleeve shirts
  • Sandals
  • Dresses
  • Rain boots
  • Waterproof luggage that you don't mind ruining
  • Skirts
  • Rain coat

August

August here can be very hot. Temperatures average in the high 80s F (low 30s C) during the day. It rains about a third of the time.

What to wear/what to pack:

  • Waterproof luggage that you don't mind ruining
  • Rain boots
  • Sandals
  • Dresses
  • Sunscreen lotion
  • Umbrella
  • Short sleeve shirts
  • Shorts
  • Rain coat
  • Skirts
  • Sunglasses

September

September in O'Fallon is pretty consistently hot. The rain can amount to several inches/centimeters.

During this time, temperatures average in the high 60s F (low 10s C) to low 80s F (high 20s C), although night temperatures can dip into the low 50s F (single digits C).

What to wear/what to pack:

  • Long and short sleeve shirts
  • Skirts
  • Sandals
  • Waterproof luggage that you don't mind ruining
  • Rain boots
  • Dresses
  • Umbrella
  • Shorts or short pants
  • Light footwear
  • Rain coat
  • Sunscreen lotion

October

October in O'Fallon is mild. The rain can amount to several inches/centimeters. During this time, temperatures average in the high 60s F (low 20s C), although night temperatures can dip into the low 40s F (single digits C).

What to wear/what to pack:

  • Umbrella
  • Socks
  • Long sleeve shirts or blouses
  • Pants or jeans
  • Standard footwear
  • Dresses
  • Long skirts
  • Waterproof luggage that you don't mind ruining
  • Rain coat
  • Light jacket or fleece
  • Rain boots

November

If you vacation in O'Fallon during November, you are likely to find that it is cool. Temperatures tend to hover around the 50s F (low 10s C) during the day, while at night they can dip into the 30s F (single digits C).

Humidity is generally between 50 and 60% during the day. In terms of precipitation, you can expect it to rain 5-10 days this month.

What to wear/what to pack:

  • Rain coat
  • Warm pants or jeans
  • Light gloves or mittens
  • Standard footwear
  • Umbrella
  • Waterproof luggage
  • Waterproof footwear
  • Socks
  • Jacket or coat
  • Fleeces

December

December in O'Fallon can be very chilly. The average overnight temperatures in the area are in the 20s F (single digits below 0 C).

It tends to rain regularly. But the colder weather doesn't bring low humidity, which is in the 60% to 70% range on average.

What to wear/what to pack:

  • Cold weather footwear
  • Sweaters
  • Waterproof footwear
  • Waterproof luggage
  • Warm pants or jeans
  • Rain coat
  • Heavy jacket
  • Heavy socks
  • Gloves or mittens
  • Umbrella

Year-round what to wear/what to pack for O'Fallon, Illinois, United States of America

Here are some general tips on what to wear in O'Fallon, as well as several items to remember to pack when traveling there.

  • A plug adadpter that supports outlet types A and B
  • A SIM card that works in O'Fallon

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