Weather in Alton, IL
Alton, Saturday, 8 August, 14:17
Clear. Feels like 101°. High 89°, low 70°.
Monthly outlook for Alton, IL: average high 86.3°, average low 69.6°. That is 0.3° above the climate normal for August. Precipitation is expected on 6 days (about 2.4 inches), against a normal of 5 days and 1.7 inches. The warmest day looks like 10 August (100°), the coolest 15 August (57.6°).
Ten-day blocks vs climate normal
| Period | Forecast high | Normal | Difference |
|---|---|---|---|
| 8 August – 17 August | 87.9° | 85.8° | +1.2° |
| 18 August – 27 August | 83.5° | 86° | -1.4° |
| 28 August – 6 September | at normal | 83.9° | — |
August records over 66 years
Climate normals and records are computed from the nearest reference point — Flordell Hills (14 mi).
0
Alton, Sunday, 9 August
Overcast. High 96°, low 74°.
0Alton, Monday, 10 August
Clear. High 100°, low 76°.
0.01
Alton, Tuesday, 11 August
Light rain. High 97°, low 78°.
0.01Alton, Wednesday, 12 August
Light rain. High 89°, low 77°.
0.55Alton, Thursday, 13 August
Rain. High 81°, low 70°.
0.01Alton, Friday, 14 August
Light rain. High 77°, low 63°.
0Alton, Saturday, 15 August
Overcast. High 78°, low 58°.
0.06Alton, Sunday, 16 August
Light rain. High 78°, low 62°.
0.23Alton, Monday, 17 August
Rain. High 94°, low 72°.
0Alton, Tuesday, 18 August
Overcast. High 87°, low 74°.
0Alton, Wednesday, 19 August
Overcast. High 93°, low 72°.
1.4Alton, Thursday, 20 August
Heavy rain. High 84°, low 73°.
0.04Alton, Friday, 21 August
Light rain. High 82°, low 69°.
0Alton, Saturday, 22 August
Overcast. High 85°, low 66°.
0.04Alton, Sunday, 23 August
Light rain. High 70°, low 61°.
0.09
Alton, Monday, 24 August
Climate normal for this date — 60-year average.
0.07Alton, Tuesday, 25 August
Climate normal for this date — 60-year average.
0.14
Alton, Wednesday, 26 August
Climate normal for this date — 60-year average.
0.13Alton, Thursday, 27 August
Climate normal for this date — 60-year average.
0.08Alton, Friday, 28 August
Climate normal for this date — 60-year average.
0.07Alton, Saturday, 29 August
Climate normal for this date — 60-year average.
0.13Alton, Sunday, 30 August
Climate normal for this date — 60-year average.
0.11Alton, Monday, 31 August
Climate normal for this date — 60-year average.
0.11Alton, Tuesday, 1 September
Climate normal for this date — 60-year average.
0.12Alton, Wednesday, 2 September
Climate normal for this date — 60-year average.
0.09Alton, Thursday, 3 September
Climate normal for this date — 60-year average.
0.12Alton, Friday, 4 September
Climate normal for this date — 60-year average.
0.04
Alton, Saturday, 5 September
Climate normal for this date — 60-year average.
0.05Alton, Sunday, 6 September
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 Alton, 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 Alton, 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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