Sioux City weather in May: Sioux City, Iowa: normal highs, lows, rain and records for May
Sioux City in May has a normal high of 72°F and a normal low of 49°F, a daily mean of 61°F, rising from 67°F on the 1st to 78°F by the 31st. Measurable precipitation falls on 12 days in a normal May, 3.87 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 22°C and low of 9°C, 98 mm of precipitation in May.
- NOAA stationSioux City Airport
- Station IDUSW00014943
- Location42.39°N 96.38°W
- Elevation1,095 ft (334 m)
- From the center7 miles
- Population86,875
- Jan 30° 10°
- Feb 34° 15°
- Mar 48° 26°
- Apr 61° 37°
- May 72° 49°
- Jun 82° 59°
- Jul 85° 63°
- Aug 83° 61°
- Sep 77° 51°
- Oct 63° 38°
- Nov 47° 25°
- Dec 33° 15°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Sioux City in May?
The normal high is 72°F and the normal low 49°F, for a daily mean of 60.5°F. May is 11.6°F warmer than April and 10.2°F cooler than June. May is the 5th warmest month of the year in Sioux City and the 3rd wettest. Across the month the normal high rises 11°F, from 67°F on May 1 to 78°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 58°F and 64°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 40%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| May 1 | 67°F | 42°F | 37% | 23% |
| May 8 | 69°F | 45°F | 38% | 23% |
| May 15 | 72°F | 48°F | 38% | 23% |
| May 22 | 75°F | 51°F | 39% | 24% |
| May 31 | 78°F | 55°F | 40% | 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 | 67°F | 42°F | 37% | 23% | 14 h |
| May 2 | 67°F | 43°F | 37% | 23% | 14 h |
| May 3 | 67°F | 43°F | 37% | 23% | 14 h 10 min |
| May 4 | 68°F | 44°F | 38% | 23% | 14 h 10 min |
| May 5 | 68°F | 44°F | 38% | 23% | 14 h 10 min |
| May 6 | 68°F | 45°F | 38% | 23% | 14 h 10 min |
| May 7 | 69°F | 45°F | 38% | 23% | 14 h 20 min |
| May 8 | 69°F | 45°F | 38% | 23% | 14 h 20 min |
| May 9 | 70°F | 46°F | 38% | 23% | 14 h 20 min |
| May 10 | 70°F | 46°F | 38% | 23% | 14 h 20 min |
| May 11 | 70°F | 47°F | 38% | 23% | 14 h 30 min |
| May 12 | 71°F | 47°F | 38% | 23% | 14 h 30 min |
| May 13 | 71°F | 48°F | 38% | 23% | 14 h 30 min |
| May 14 | 72°F | 48°F | 38% | 23% | 14 h 30 min |
| May 15 | 72°F | 48°F | 38% | 23% | 14 h 30 min |
| May 16 | 72°F | 49°F | 38% | 23% | 14 h 40 min |
| May 17 | 73°F | 49°F | 38% | 24% | 14 h 40 min |
| May 18 | 73°F | 50°F | 38% | 24% | 14 h 40 min |
| May 19 | 74°F | 50°F | 39% | 24% | 14 h 40 min |
| May 20 | 74°F | 50°F | 39% | 24% | 14 h 40 min |
| May 21 | 74°F | 51°F | 39% | 24% | 14 h 50 min |
| May 22 | 75°F | 51°F | 39% | 24% | 14 h 50 min |
| May 23 | 75°F | 52°F | 39% | 25% | 14 h 50 min |
| May 24 | 75°F | 52°F | 40% | 25% | 14 h 50 min |
| May 25 | 76°F | 53°F | 40% | 25% | 14 h 50 min |
| May 26 | 76°F | 53°F | 40% | 25% | 14 h 50 min |
| May 27 | 77°F | 53°F | 40% | 25% | 15 h |
| May 28 | 77°F | 54°F | 40% | 25% | 15 h |
| May 29 | 77°F | 54°F | 40% | 25% | 15 h |
| May 30 | 78°F | 55°F | 40% | 25% | 15 h |
| May 31 | 78°F | 55°F | 40% | 25% | 15 h |
- Normal high
- 72°FMay average
- Normal low
- 49°FMay average
- Precipitation
- 3.87 inmonth total
- Days with precipitation
- 120.01 inch or more
- Days at 90°F or more
- 2
- Nights at 32°F or colder
- 1
- Daylight
- 14 h to 15 hMay 1 to May 31
- Days at 70°F or more
- 20
- Days at 80°F or more
- 9
- Sunshine
- 72%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00014943; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Sioux City in May?
On a given May day the chance of 0.01 inch or more is 39% on average, highest around May 31 (40%). In all, 3.87 in falls on 12 days of a normal May, 1 of them with an inch or more.
In a normal May in Sioux City, 2 days reach 90°F and 1 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00014943.
How humid and windy is Sioux City in May?
At 3 p.m. the normal temperature is 75°F with 47% relative humidity and a dew point of 54°F; at 6 a.m. it is 58°F with 84% humidity. The wind averages 10.0 mph, most often from the south-southwest in the afternoon.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 58°F | 53°F | 84% | 7.5 mph | 56% |
| 9 a.m. | 67°F | 55°F | 66% | 10.9 mph | 63% |
| noon | 73°F | 54°F | 52% | 12.7 mph | 52% |
| 3 p.m. | 75°F | 54°F | 47% | 13.2 mph | 57% |
| 6 p.m. | 74°F | 53°F | 48% | 11.8 mph | 61% |
| 9 p.m. | 66°F | 54°F | 64% | 8.4 mph | 66% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014943. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for May in Sioux City?
The warmest May temperature on Sioux City's official record (since 1889) is 106°F, on May 14, 2013; the coldest is 23°F, on May 1, 1909. The wettest May brought 11.78 in (1903); the snowiest, 5.1 inches (1917).
The May mean against the 1991-2020 normal of 60.5°F: 2021 59.2°F (−1.3), 2022 61.2°F (+0.7), 2023 64.8°F (+4.3), 2024 61.4°F (+0.9), 2025 60.0°F (−0.5), 2026 62.2°F (+1.7). 4 of 6 ran warmer than normal.
| May | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 59.2°F | −1.3°F | 2.77 in |
| 2022 | 61.2°F | +0.7°F | 2.18 in |
| 2023 | 64.8°F | +4.3°F | 4.40 in |
| 2024 | 61.4°F | +0.9°F | 5.75 in |
| 2025 | 60.0°F | −0.5°F | 1.91 in |
| 2026 | 62.2°F | +1.7°F | 2.95 in |
Source: records: ACIS, NWS threaded record SUXthr; recent months: ACIS, station USW00014943. Records and recent months use complete months only.
How does May in Sioux City compare across Iowa?
Across the 132 places PlainClimate covers in Iowa, May normal highs run from 66°F in Northwood to 74°F in Glenwood; Sioux City's is 72°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.