Weather in Decatur, IL
Decatur, Friday, 16 October, 00:27
Overcast. Feels like 57°. High 58°, low 50°.
Monthly outlook for Decatur, IL: average high 67.6°, average low 49.3°. That is 3.4° above the climate normal for October. Precipitation is expected on 3 days (about 0.9 inches), against a normal of 5 days and 1.8 inches. The warmest day looks like 23 October (77.2°), the coolest 17 October (39.2°).
Ten-day blocks vs climate normal
| Period | Forecast high | Normal | Difference |
|---|---|---|---|
| 16 October – 25 October | 69° | 62.4° | +3.6° |
| 26 October – 4 November | 65.3° | 58.9° | +3.6° |
| 5 November – 14 November | at normal | 53.5° | — |
October records over 66 years
Climate normals and records are computed from the nearest reference point — Lake City (13 mi).
0
Decatur, Saturday, 17 October
Clear. High 57°, low 39°.
0Decatur, Sunday, 18 October
Clear. High 63°, low 42°.
0Decatur, Monday, 19 October
Clear. High 67°, low 43°.
0Decatur, Tuesday, 20 October
Clear. High 69°, low 46°.
0Decatur, Wednesday, 21 October
Overcast. High 72°, low 52°.
0
Decatur, Thursday, 22 October
Mostly clear. High 77°, low 54°.
0Decatur, Friday, 23 October
Clear. High 77°, low 55°.
0Decatur, Saturday, 24 October
Overcast. High 75°, low 57°.
0Decatur, Sunday, 25 October
Overcast. High 75°, low 56°.
0Decatur, Monday, 26 October
Overcast. High 74°, low 55°.
0Decatur, Tuesday, 27 October
Clear. High 66°, low 47°.
0.71
Decatur, Wednesday, 28 October
Heavy rain. High 62°, low 51°.
0.11Decatur, Thursday, 29 October
Light rain. High 59°, low 47°.
0
Decatur, Friday, 30 October
Partly cloudy. High 65°, low 46°.
0Decatur, Saturday, 31 October
Overcast. High 66°, low 49°.
0.2Decatur, Sunday, 1 November
Climate normal for this date — 60-year average.
0.09Decatur, Monday, 2 November
Climate normal for this date — 60-year average.
0.09Decatur, Tuesday, 3 November
Climate normal for this date — 60-year average.
0.1Decatur, Wednesday, 4 November
Climate normal for this date — 60-year average.
0.11Decatur, Thursday, 5 November
Climate normal for this date — 60-year average.
0.08Decatur, Friday, 6 November
Climate normal for this date — 60-year average.
0.09Decatur, Saturday, 7 November
Climate normal for this date — 60-year average.
0.04Decatur, Sunday, 8 November
Climate normal for this date — 60-year average.
0.11
Decatur, Monday, 9 November
Climate normal for this date — 60-year average.
0.14Decatur, Tuesday, 10 November
Climate normal for this date — 60-year average.
0.1Decatur, Wednesday, 11 November
Climate normal for this date — 60-year average.
0.07Decatur, Thursday, 12 November
Climate normal for this date — 60-year average.
0.07Decatur, Friday, 13 November
Climate normal for this date — 60-year average.
0.09Decatur, Saturday, 14 November
Climate normal for this date — 60-year average.
About the monthly outlook
How accurate is a 30-day forecast?
The first 16 days come from weather models — reliable for the first 3–5 days and progressively less so after that. Days 17 through 30 for Decatur, IL are built from the climate normal, the 60-year average, so they show typical weather for those dates rather than a specific forecast.
What does "above normal" mean?
We compare the forecast against the climate normal for those exact calendar days, computed from 60 years of observations. The deviation shows how much the coming month differs from a typical one.
Where do the 66-year records come from?
They are real temperature extremes recorded in Decatur, IL since 1960: the highest and lowest reading for each calendar date, with the year it happened.
How often is it updated?
The forecast portion refreshes every hour; the climate portion is based on long-term data and stays stable.
Sun and moon today
Weather history
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