Best time to visit St. Johns, IL

A month-by-month travel weather guide based on NOAA 30-year climate normals.

The most comfortable travel window in St. Johns runs from June through October — 5 months of pleasant temperatures and modest rainfall.

January Cold
High
40.4°F
Low
23.9°F
Precip
3.16 in

Winter weather. Plan around weather; good for snow sports if applicable.

Daylight ≈ 9h 38m

February Cool
High
45.7°F
Low
27.7°F
Precip
2.90 in

Mild but on the chilly side. Pack a jacket; great for hiking and city walks.

Daylight ≈ 10h 35m

March Cool
High
55.9°F
Low
36.1°F
Precip
4.39 in

Mild but on the chilly side. Pack a jacket; great for hiking and city walks.

Daylight ≈ 11h 45m

April Wet
High
67.5°F
Low
46.1°F
Precip
5.35 in

Frequent rain. Bring waterproof gear; outdoor plans need flexibility.

Daylight ≈ 12h 60m

May Wet
High
76.1°F
Low
56.1°F
Precip
5.51 in

Frequent rain. Bring waterproof gear; outdoor plans need flexibility.

Daylight ≈ 14h 3m

June Good
High
84.4°F
Low
64.3°F
Precip
4.79 in

Comfortable for most activities. Bring layers; nights can be cool.

Daylight ≈ 14h 36m

July Good
High
87.2°F
Low
67.6°F
Precip
3.94 in

Comfortable for most activities. Bring layers; nights can be cool.

Daylight ≈ 14h 24m

August Good
High
86.4°F
Low
64.9°F
Precip
3.30 in

Comfortable for most activities. Bring layers; nights can be cool.

Daylight ≈ 13h 29m

September Excellent
High
80.0°F
Low
56.6°F
Precip
3.40 in

Sweet spot — comfortable highs in the 65-80°F range, mild nights, low rain. Ideal for nearly any outdoor plan.

Daylight ≈ 12h 14m

October Good
High
69.0°F
Low
46.0°F
Precip
3.66 in

Comfortable for most activities. Bring layers; nights can be cool.

Daylight ≈ 10h 59m

November Cool
High
55.0°F
Low
35.5°F
Precip
4.07 in

Mild but on the chilly side. Pack a jacket; great for hiking and city walks.

Daylight ≈ 9h 54m

December Cold
High
44.4°F
Low
28.0°F
Precip
3.24 in

Winter weather. Plan around weather; good for snow sports if applicable.

Daylight ≈ 9h 22m

Looking for similar climates? See St. Johns's climate twins. Or jump straight to the full climate profile.