Alton climate

Alton Weather in September

NOAA 1991-2020 normals for La Joya, 4.2 km from Alton

Average highs run from 95°F on September 1 to 90°F on September 30, and lows from 74°F to 68°F. Normal precipitation for the month is 3.50 in over about 6 wet days.

September day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Alton, in °F, with the record for each date.406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

September at a glance

Average high
92°F
Average low
71°F
Precipitation
3.50 in
Record high
108°FSep 4, 2011
Record low
54°FSep 30, 2020
Chance of a freeze
0%
Days of 90°F or more
26.2
Daylight
12 h 40 min to 11 h 56 min
Cloud cover
46%
Humidity
69%
Dew point
69°F
Wind
8.9 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
Sep 195°F74°F106°F 201871°F 196719%0%
Sep 295°F74°F106°F 201870°F 199019%0%
Sep 395°F74°F106°F 201170°F 197419%0%
Sep 494°F73°F108°F 201167°F 197420%0%
Sep 594°F73°F107°F 200062°F 197420%0%
Sep 694°F73°F106°F 200065°F 198820%0%
Sep 794°F73°F105°F 202667°F 201120%0%
Sep 894°F73°F106°F 202664°F 197420%0%
Sep 993°F73°F104°F 202664°F 198820%0%
Sep 1093°F72°F107°F 202666°F 198820%0%
Sep 1193°F72°F106°F 202665°F 202020%0%
Sep 1293°F72°F104°F 202668°F 201720%0%
Sep 1393°F72°F104°F 198769°F 196920%0%
Sep 1492°F72°F104°F 198766°F 197720%0%
Sep 1592°F71°F103°F 200964°F 196120%0%
Sep 1692°F71°F103°F 196863°F 197920%0%
Sep 1792°F71°F104°F 201661°F 200820%0%
Sep 1892°F71°F106°F 201660°F 198120%0%
Sep 1991°F71°F104°F 201658°F 198120%0%
Sep 2091°F70°F103°F 201659°F 199120%0%
Sep 2191°F70°F102°F 201659°F 198319%0%
Sep 2291°F70°F102°F 202357°F 199519%0%
Sep 2391°F70°F105°F 200556°F 197519%0%
Sep 2491°F69°F105°F 200555°F 197519%0%
Sep 2590°F69°F104°F 200559°F 197518%0%
Sep 2690°F69°F103°F 201158°F 199118%0%
Sep 2790°F69°F102°F 196655°F 197017%0%
Sep 2890°F68°F104°F 200555°F 197017%0%
Sep 2990°F68°F101°F 200556°F 198417%0%
Sep 3090°F68°F101°F 198654°F 202016%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Alton, in percent, and of at least 0.1 inch of snowfall.05101520251102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (CDT).

September 1
sunrise 7:13 AM, sunset 7:53 PM
September 30
sunrise 7:25 AM, sunset 7:21 PM

Every day of September: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00414911 (La Joya), public domain. Records: NOAA GHCN-Daily, station USW00012959, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.