Weather in Decatur, IL
Decatur, Sunday, 11 October, 09:02
Clear. Feels like 59°. High 80°, low 55°.
Monthly outlook for Decatur, IL: average high 71.7°, average low 53°. That is 4.5° above the climate normal for October. Precipitation is expected on 4 days (about 1.5 inches), against a normal of 5 days and 1.9 inches. The warmest day looks like 13 October (88.1°), the coolest 18 October (32°).
Ten-day blocks vs climate normal
| Period | Forecast high | Normal | Difference |
|---|---|---|---|
| 11 October – 20 October | 71.3° | 64.7° | +3.7° |
| 21 October – 30 October | 72.2° | 61° | +6.2° |
| 31 October – 9 November | at normal | 56.7° | — |
October records over 66 years
Climate normals and records are computed from the nearest reference point — Lake City (13 mi).
0
Decatur, Monday, 12 October
Overcast. High 87°, low 57°.
0Decatur, Tuesday, 13 October
Clear. High 88°, low 70°.
0.57
Decatur, Wednesday, 14 October
Rain. High 78°, low 69°.
0.21Decatur, Thursday, 15 October
Light rain. High 76°, low 64°.
0.28Decatur, Friday, 16 October
Rain. High 71°, low 51°.
0Decatur, Saturday, 17 October
Clear. High 46°, low 35°.
0Decatur, Sunday, 18 October
Clear. High 54°, low 32°.
0
Decatur, Monday, 19 October
Partly cloudy. High 65°, low 40°.
0Decatur, Tuesday, 20 October
Overcast. High 68°, low 45°.
0Decatur, Wednesday, 21 October
Overcast. High 70°, low 52°.
0Decatur, Thursday, 22 October
Overcast. High 73°, low 52°.
0Decatur, Friday, 23 October
Overcast. High 78°, low 58°.
0
Decatur, Saturday, 24 October
Mostly clear. High 77°, low 59°.
0.39Decatur, Sunday, 25 October
Rain. High 81°, low 61°.
0Decatur, Monday, 26 October
Overcast. High 54°, low 48°.
0.09
Decatur, Tuesday, 27 October
Climate normal for this date — 60-year average.
0.06Decatur, Wednesday, 28 October
Climate normal for this date — 60-year average.
0.07Decatur, Thursday, 29 October
Climate normal for this date — 60-year average.
0.11Decatur, Friday, 30 October
Climate normal for this date — 60-year average.
0.17Decatur, Saturday, 31 October
Climate normal for this date — 60-year average.
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.
0.11Decatur, Monday, 9 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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