O'Fallon Weather Forecast 15 Days, Weather in O'Fallon Today
Current weather conditions and 15 day weather forecast for O'Fallon, Illinois, USA including weather daily high/low temperature, warnings, chance of precipitation, pressure, humidity/wind chill, rain risk, wind speed, cloud, pressure, and UV index.
Current weather conditions at O'Fallon
| 23 September 2026 Wednesday 19.6 ° C / 67.2°F  Cloudy |
Feels Like : 17.5 ° C / 63.5°F Humidity : % 62 Pressure : 1025 mb Wind Speed : 14.4 kmph / 8.9 miles from NNE  Visibility : 10 km Precipitation (rainfall) : 0 mm Cloud (%) : 84 |
15 day weather forecast for O'Fallon, IL, USA
Weather Forecast for next 15 Days for O'Fallon including weather warnings, temperature, rain, wind speed, cloud, snow, wind speed and wind direction, pressure and UV index.Here is weather for the next 15 days in O'Fallon, Illinois state, US. To see the daily forecast, scroll to the table below.
| Date | Weather forecast | Low temperature | High temperature | Avg. temperature | Humidity | Chance of rain | UV Index | Sun Position | Moon Position | |
|---|---|---|---|---|---|---|---|---|---|---|
| 23 September 2026 Wednesday |  Sunny |
13.8 ° C (56.9°F) |
23.3 ° C (74°F) |
17.8 ° C (64.1°F) |
% 73 | 12% | 5 | Sunrise:06:48 AM Sunset: 06:55 PM |
Moonrise:05:36 PM Moonset: 03:50 AM Moon Phase ( Waxing Gibbous ) |
|
| 24 September 2026 Thursday | Sunny |
13.1 ° C (55.5°F) |
25.4 ° C (77.7°F) |
18.7 ° C (65.6°F) |
% 72 | 7% | 6.5 | Sunrise:06:49 AM Sunset: 06:54 PM |
Moonrise:05:58 PM Moonset: 04:50 AM Moon Phase ( Full Moon ) |
|
| 25 September 2026 Friday |  Overcast |
16 ° C (60.8°F) |
26.4 ° C (79.6°F) |
20.1 ° C (68.2°F) |
% 68 | 12% | 5.9 | Sunrise:06:50 AM Sunset: 06:52 PM |
Moonrise:06:19 PM Moonset: 05:50 AM Moon Phase ( Full Moon ) |
|
| 26 September 2026 Saturday | Overcast |
13 ° C (55.5°F) |
23.1 ° C (73.6°F) |
16.8 ° C (62.2°F) |
% 60 | 68% | 1.3 | Sunrise:06:51 AM Sunset: 06:50 PM |
Moonrise:06:41 PM Moonset: 06:50 AM Moon Phase ( Full Moon ) |
|
| 27 September 2026 Sunday | Overcast |
14.1 ° C (57.4°F) |
19.3 ° C (66.7°F) |
16 ° C (60.8°F) |
% 72 | 75% | 4 | Sunrise:06:51 AM Sunset: 06:49 PM |
Moonrise:07:05 PM Moonset: 07:52 AM Moon Phase ( Waning Gibbous ) |
|
| 28 September 2026 Monday | Overcast |
13.7 ° C (56.7°F) |
21.2 ° C (70.2°F) |
17.4 ° C (63.4°F) |
% 73 | 24% | 5 | Sunrise:06:52 AM Sunset: 06:47 PM |
Moonrise:07:31 PM Moonset: 08:57 AM Moon Phase ( Waning Gibbous ) |
|
| 29 September 2026 Tuesday |  Patchy rain nearby |
13.2 ° C (55.7°F) |
26.9 ° C (80.3°F) |
19.1 ° C (66.3°F) |
% 84 | 61% | 6 | Sunrise:06:53 AM Sunset: 06:46 PM |
Moonrise:08:03 PM Moonset: 10:04 AM Moon Phase ( Waning Gibbous ) |
|
| 30 September 2026 Wednesday | Sunny |
13.6 ° C (56.4°F) |
21.2 ° C (70.2°F) |
18.1 ° C (64.5°F) |
% 64 | 57% | 6 | Sunrise:06:54 AM Sunset: 06:44 PM |
Moonrise:08:42 PM Moonset: 11:12 AM Moon Phase ( Waning Gibbous ) |
|
| 01 October 2026 Thursday | Sunny |
10.7 ° C (51.3°F) |
23.6 ° C (74.5°F) |
17 ° C (62.6°F) |
% 50 | 2% | 6 | Sunrise:06:55 AM Sunset: 06:43 PM |
Moonrise:09:30 PM Moonset: 12:21 PM Moon Phase ( Last Quarter ) |
|
| 02 October 2026 Friday | Sunny |
15.6 ° C (60.1°F) |
31.1 ° C (88.1°F) |
22.3 ° C (72.1°F) |
% 42 | 2% | 8 | Sunrise:06:56 AM Sunset: 06:41 PM |
Moonrise:10:28 PM Moonset: 01:25 PM Moon Phase ( Last Quarter ) |
|
| 03 October 2026 Saturday | Overcast |
17.6 ° C (63.6°F) |
25 ° C (76.9°F) |
20.7 ° C (69.2°F) |
% 56 | 10% | 5 | Sunrise:06:57 AM Sunset: 06:39 PM |
Moonrise:11:36 PM Moonset: 02:22 PM Moon Phase ( Last Quarter ) |
|
| 04 October 2026 Sunday | Sunny |
11.1 ° C (52°F) |
22.7 ° C (72.9°F) |
16.7 ° C (62°F) |
% 54 | 2% | 6 | Sunrise:06:58 AM Sunset: 06:38 PM |
Moonrise:Does not rise today Moonset: 03:10 PM Moon Phase ( Last Quarter ) |
|
| 05 October 2026 Monday | Overcast |
12.2 ° C (54°F) |
28 ° C (82.3°F) |
19.5 ° C (67.2°F) |
% 45 | 6% | 7 | Sunrise:06:59 AM Sunset: 06:36 PM |
Moonrise:12:49 AM Moonset: 03:50 PM Moon Phase ( Waning Crescent ) |
|
| 06 October 2026 Tuesday | Sunny |
18.5 ° C (65.3°F) |
28.2 ° C (82.7°F) |
22.4 ° C (72.3°F) |
% 55 | 4% | 7 | Sunrise:07:00 AM Sunset: 06:35 PM |
Moonrise:02:05 AM Moonset: 04:24 PM Moon Phase ( Waning Crescent ) |
|
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