Temperature
Warm by day, brisk at night.
80°Ftypical September high
Typical range
September climate
September in Alton
United States · North America
Warm days and plenty of sun.
One of the best months here
Late
Daytime high
80°F
Lows around 60°F
Rain
Several rainy days
Sun
10 h/day
Air feel
Comfortable
When to visit
Month-by-month fit
Best
Precipitation
Several rainy days, mostly brief and on-and-off. About 7 wet days, the lowest monthly average.
23%wet-day frequency
AmountWet-day chance
Sunshine
Plenty of sun this month.
10 hSeptember sunshine
Heat & humidity by month
Warm days with mostly dry air.
LowSeptember Heat feel
Easy airWarm airHot airHumid airVery humid air
Hourly temperature pattern
In September, afternoons feel about 78° and nights feel near 63°.
FreezingVery coldColdCoolComfortableWarmHotNight hours
Clear sky
Partly cloudy skies this month.
58%September Clear sky
Clear skyCloud
Wind pattern
Calm winds are typical in September.
6 mphSeptember Calm
More detailIncludes daypart comfort
Typical September day
September late afternoons are around 78°F, easing to about 74°F in early evening.
Avg temp Typical range
Morning68°F
Rain9%
Cloud42%
Humid airModerate
Sun intensityLow
Best windowMidday77°F
Rain11%
Cloud44%
Humid airModerate
Sun intensityStrong
Late afternoon78°F
Rain11%
Cloud45%
Humid airModerate
Sun intensityModerate
Early evening74°F
Rain10%
Cloud42%
Humid airModerate
Sun intensityMinimal
Data tableView month-by-month numbers
View month-by-month numbers
| Month | High°F | Low°F | Rainin | Wet days | Sunh | Humidity% |
|---|---|---|---|---|---|---|
| Jan | 39 | 24 | 2.6 | 8 | 6.0 | 71 |
| Feb | 45 | 28 | 2.5 | 8 | 7.1 | 69 |
| Mar | 56 | 38 | 3.8 | 11 | 8.1 | 65 |
| Apr | 68 | 48 | 4.4 | 11 | 9.0 | 62 |
| May | 76 | 58 | 5.0 | 13 | 10.4 | 67 |
| Jun | 85 | 67 | 4.0 | 11 | 11.7 | 68 |
| Jul | 87 | 71 | 3.4 | 10 | 12.2 | 71 |
| Aug | 86 | 68 | 2.9 | 8 | 11.5 | 72 |
| Sep | 80 | 60 | 3.1 | 7 | 10.0 | 69 |
| Oct | 68 | 49 | 3.3 | 9 | 8.1 | 68 |
| Nov | 55 | 38 | 3.1 | 8 | 6.6 | 69 |
| Dec | 44 | 29 | 2.6 | 8 | 5.8 | 73 |
Similar climates
Similar
Similar travel styleAkronUnited StatesSimilar travel styleAlbiaUnited StatesSimilar travel styleAlexandriaUnited StatesSimilar travel styleAllentownUnited States
Want a side-by-side climate view? Compare Alton with Akron.
Climate data notePlanning guidance, not a forecast
Typical monthly values are based on long-term climate records. Useful for planning, not a forecast. Check the weather before you travel.
Sunshine: source type is not yet identified at metric level.
Local microclimates can vary by beach, neighborhood, trail, or elevation.
Last updated: Jul 31, 2026
Data & methodology