St. Johns Weather Forecast 15 Days, Weather in St. Johns Today
Current weather conditions and 15 day weather forecast for St. Johns, 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 St. Johns
| 20 September 2026 Sunday 34.8 ° C / 94.7°F  Overcast |
Feels Like : 32.6 ° C / 90.7°F Humidity : % 25 Pressure : 1011 mb Wind Speed : 15.1 kmph / 9.4 miles from W  Visibility : 10 km Precipitation (rainfall) : 0 mm Cloud (%) : 100 |
15 day weather forecast for St. Johns, IL, USA
Weather Forecast for next 15 Days for St. Johns 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 St. Johns, 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 | |
|---|---|---|---|---|---|---|---|---|---|---|
| 20 September 2026 Sunday | Overcast |
24.3 ° C (75.7°F) |
36.1 ° C (97°F) |
29.3 ° C (84.8°F) |
% 41 | 8% | 7 | Sunrise:06:43 AM Sunset: 06:57 PM |
Moonrise:04:09 PM Moonset: 12:46 AM Moon Phase ( Waxing Gibbous ) |
|
| 21 September 2026 Monday |  Light rain shower |
19.4 ° C (66.9°F) |
29.4 ° C (84.8°F) |
23.4 ° C (74.2°F) |
% 77 | 79% | 5.7 | Sunrise:06:43 AM Sunset: 06:56 PM |
Moonrise:04:41 PM Moonset: 01:47 AM Moon Phase ( Waxing Gibbous ) |
|
| 22 September 2026 Tuesday |  Patchy rain nearby |
14.9 ° C (58.8°F) |
26.6 ° C (79.8°F) |
19.9 ° C (67.7°F) |
% 74 | 64% | 5.7 | Sunrise:06:44 AM Sunset: 06:54 PM |
Moonrise:05:08 PM Moonset: 02:48 AM Moon Phase ( Waxing Gibbous ) |
|
| 23 September 2026 Wednesday |  Sunny |
15.2 ° C (59.4°F) |
25.6 ° C (78°F) |
19.6 ° C (67.3°F) |
% 68 | 5% | 6.2 | Sunrise:06:45 AM Sunset: 06:52 PM |
Moonrise:05:33 PM Moonset: 03:48 AM Moon Phase ( Waxing Gibbous ) |
|
| 24 September 2026 Thursday | Sunny |
12.3 ° C (54.2°F) |
25.9 ° C (78.6°F) |
18.5 ° C (65.3°F) |
% 71 | 10% | 7 | Sunrise:06:46 AM Sunset: 06:51 PM |
Moonrise:05:55 PM Moonset: 04:48 AM Moon Phase ( Full Moon ) |
|
| 25 September 2026 Friday | Light rain shower |
15.8 ° C (60.5°F) |
17.7 ° C (63.8°F) |
16.4 ° C (61.5°F) |
% 88 | 91% | 4 | Sunrise:06:47 AM Sunset: 06:49 PM |
Moonrise:06:17 PM Moonset: 05:47 AM Moon Phase ( Full Moon ) |
|
| 26 September 2026 Saturday | Sunny |
14.8 ° C (58.7°F) |
25.3 ° C (77.5°F) |
19.2 ° C (66.6°F) |
% 72 | 10% | 7 | Sunrise:06:48 AM Sunset: 06:48 PM |
Moonrise:06:39 PM Moonset: 06:47 AM Moon Phase ( Full Moon ) |
|
| 27 September 2026 Sunday | Sunny |
14.9 ° C (58.9°F) |
27.2 ° C (80.9°F) |
20.5 ° C (68.9°F) |
% 54 | 3% | 7 | Sunrise:06:49 AM Sunset: 06:46 PM |
Moonrise:07:03 PM Moonset: 07:49 AM Moon Phase ( Waning Gibbous ) |
|
| 28 September 2026 Monday | Overcast |
12 ° C (53.6°F) |
19 ° C (66.1°F) |
16.8 ° C (62.2°F) |
% 70 | 59% | 4 | Sunrise:06:50 AM Sunset: 06:45 PM |
Moonrise:07:30 PM Moonset: 08:53 AM Moon Phase ( Waning Gibbous ) |
|
| 29 September 2026 Tuesday | Sunny |
6.8 ° C (44.2°F) |
19.5 ° C (67.2°F) |
12.7 ° C (54.9°F) |
% 50 | 2% | 5 | Sunrise:06:50 AM Sunset: 06:43 PM |
Moonrise:08:02 PM Moonset: 09:59 AM Moon Phase ( Waning Gibbous ) |
|
| 30 September 2026 Wednesday | Sunny |
10.9 ° C (51.5°F) |
25.7 ° C (78.2°F) |
17.1 ° C (62.7°F) |
% 37 | 3% | 7 | Sunrise:06:51 AM Sunset: 06:42 PM |
Moonrise:08:41 PM Moonset: 11:08 AM Moon Phase ( Waning Gibbous ) |
|
| 01 October 2026 Thursday | Sunny |
9.2 ° C (48.5°F) |
21.7 ° C (71.1°F) |
15.6 ° C (60.1°F) |
% 50 | 2% | 6 | Sunrise:06:52 AM Sunset: 06:40 PM |
Moonrise:09:29 PM Moonset: 12:16 PM Moon Phase ( Last Quarter ) |
|
| 02 October 2026 Friday | Sunny |
11.2 ° C (52.1°F) |
24.4 ° C (76°F) |
17.2 ° C (63°F) |
% 42 | 1% | 6 | Sunrise:06:53 AM Sunset: 06:38 PM |
Moonrise:10:28 PM Moonset: 01:20 PM Moon Phase ( Last Quarter ) |
|
| 03 October 2026 Saturday | Overcast |
11.8 ° C (53.3°F) |
22 ° C (71.6°F) |
17.5 ° C (63.4°F) |
% 38 | 7% | 5 | Sunrise:06:54 AM Sunset: 06:37 PM |
Moonrise:11:35 PM Moonset: 02:17 PM Moon Phase ( Last Quarter ) |
|
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