St. Charles weather in May: St. Charles, Missouri: normal highs, lows, rain and records for May
St. Charles in May has a normal high of 77°F and a normal low of 56°F, a daily mean of 67°F, rising from 73°F on the 1st to 82°F by the 31st. Measurable precipitation falls on 13 days in a normal May, 4.60 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 25°C and low of 13°C, 117 mm of precipitation in May.
- NOAA stationSt Charles County Airport
- Station IDUSW00053904
- Location38.93°N 90.43°W
- Elevation436 ft (133 m)
- Population72,458
- Jan 40° 22°
- Feb 45° 26°
- Mar 56° 34°
- Apr 68° 45°
- May 77° 56°
- Jun 86° 65°
- Jul 89° 68°
- Aug 88° 66°
- Sep 81° 57°
- Oct 69° 46°
- Nov 55° 35°
- Dec 44° 27°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is St. Charles in May?
The normal high is 77°F and the normal low 56°F, for a daily mean of 66.6°F. May is 9.9°F warmer than April and 8.8°F cooler than June. May is the 5th warmest month of the year in St. Charles and the wettest. Across the month the normal high rises 9°F, from 73°F on May 1 to 82°F on May 31. From one year to the next May's mean temperature typically moves about 3.0°F either way (NOAA's standard deviation), so roughly two Mays in three average between 64°F and 70°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 41%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 73°F | 51°F | 39% | 25% |
| May 8 | 75°F | 53°F | 40% | 25% |
| May 15 | 77°F | 56°F | 41% | 25% |
| May 22 | 79°F | 58°F | 41% | 25% |
| May 31 | 82°F | 61°F | 41% | 25% |
Every day of May: normal high, low and chance of precipitation (warmest afternoon May 31, coldest night May 1)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| May 1 | 73°F | 51°F | 39% | 25% | 13 h 50 min |
| May 2 | 73°F | 51°F | 39% | 25% | 13 h 50 min |
| May 3 | 74°F | 52°F | 39% | 25% | 13 h 50 min |
| May 4 | 74°F | 52°F | 39% | 25% | 13 h 50 min |
| May 5 | 74°F | 52°F | 39% | 25% | 14 h |
| May 6 | 74°F | 53°F | 39% | 25% | 14 h |
| May 7 | 75°F | 53°F | 39% | 25% | 14 h |
| May 8 | 75°F | 53°F | 40% | 25% | 14 h |
| May 9 | 75°F | 54°F | 40% | 25% | 14 h |
| May 10 | 76°F | 54°F | 40% | 25% | 14 h 10 min |
| May 11 | 76°F | 54°F | 40% | 25% | 14 h 10 min |
| May 12 | 76°F | 55°F | 40% | 25% | 14 h 10 min |
| May 13 | 76°F | 55°F | 40% | 25% | 14 h 10 min |
| May 14 | 77°F | 55°F | 41% | 25% | 14 h 10 min |
| May 15 | 77°F | 56°F | 41% | 25% | 14 h 20 min |
| May 16 | 77°F | 56°F | 41% | 25% | 14 h 20 min |
| May 17 | 78°F | 56°F | 41% | 25% | 14 h 20 min |
| May 18 | 78°F | 57°F | 41% | 25% | 14 h 20 min |
| May 19 | 78°F | 57°F | 41% | 25% | 14 h 20 min |
| May 20 | 78°F | 57°F | 41% | 25% | 14 h 20 min |
| May 21 | 79°F | 58°F | 41% | 25% | 14 h 30 min |
| May 22 | 79°F | 58°F | 41% | 25% | 14 h 30 min |
| May 23 | 79°F | 58°F | 41% | 25% | 14 h 30 min |
| May 24 | 80°F | 59°F | 41% | 25% | 14 h 30 min |
| May 25 | 80°F | 59°F | 41% | 25% | 14 h 30 min |
| May 26 | 80°F | 59°F | 41% | 25% | 14 h 30 min |
| May 27 | 81°F | 60°F | 41% | 25% | 14 h 40 min |
| May 28 | 81°F | 60°F | 41% | 25% | 14 h 40 min |
| May 29 | 81°F | 60°F | 41% | 25% | 14 h 40 min |
| May 30 | 82°F | 61°F | 41% | 25% | 14 h 40 min |
| May 31 | 82°F | 61°F | 41% | 25% | 14 h 40 min |
- Normal high
- 77°FMay average
- Normal low
- 56°FMay average
- Precipitation
- 4.60 inmonth total
- Days with precipitation
- 130.01 inch or more
- Days at 90°F or more
- 2
- Daylight
- 13 h 50 min to 14 h 40 minMay 1 to May 31
- Days at 70°F or more
- 24
- Days at 80°F or more
- 14
- Sunshine
- 74%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00053904; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in St. Charles in May?
On a given May day the chance of 0.01 inch or more is 40% on average, highest around May 25 (41%). In all, 4.60 in falls on 13 days of a normal May, 1 of them with an inch or more.
In a normal May in St. Charles, 2 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00053904.
What are the records for May in St. Charles?
The May mean against the 1991-2020 normal of 66.6°F: 2021 64.7°F (−1.9), 2022 68.0°F (+1.4), 2023 68.0°F (+1.4), 2024 70.3°F (+3.7), 2025 64.5°F (−2.1), 2026 65.8°F (−0.8). 3 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 64.7°F | −1.9°F | 3.19 in |
| 2022 | 68.0°F | +1.4°F | 5.37 in |
| 2023 | 68.0°F | +1.4°F | 1.15 in |
| 2024 | 70.3°F | +3.7°F | 5.09 in |
| 2025 | 64.5°F | −2.1°F | 3.08 in |
| 2026 | 65.8°F | −0.8°F | 3.48 in |
Source: recent months: ACIS, station USW00053904. Records and recent months use complete months only.
How does May in St. Charles compare across Missouri?
Across the 134 places PlainClimate covers in Missouri, May normal highs run from 71°F in Green City to 81°F in Malden; St. Charles's is 77°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.