Sioux City Ang, Iowa climate: Climate normals at a NOAA weather station
Sioux City Ang's normal year runs from 9°F January nights to 86°F July afternoons, with 30.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.9°C, January lows of −13°C, July highs of 30°C, 769 mm of precipitation a year.
- NOAA stationSioux City Ang
- Station IDUSC00137702
- Location42.40°N 96.38°W
- Elevation1,100 ft (335 m)
On October 23, the normal high in Sioux City Ang is 60°F and the normal low 34°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sioux City Ang.
- Jan 30° 9°
- Feb 35° 13°
- Mar 47° 24°
- Apr 61° 35°
- May 72° 47°
- Jun 82° 58°
- Jul 86° 63°
- Aug 83° 61°
- Sep 77° 51°
- Oct 64° 37°
- Nov 47° 24°
- Dec 34° 14°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Sioux City Ang each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 9°F. The most precipitation falls in June (4.62 in), the least in January (0.66 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 30°F | 9°F | 19.2°F | 0.66 | – | <1 | 31 | 9 h 20 min |
| February | 35°F | 13°F | 23.5°F | 0.88 | – | <1 | 28 | 10 h 30 min |
| March | 47°F | 24°F | 35.6°F | 1.62 | – | <1 | 24 | 11 h 50 min |
| April | 61°F | 35°F | 47.7°F | 3.07 | – | <1 | 12 | 13 h 20 min |
| May | 72°F | 47°F | 59.4°F | 4.44 | – | 2 | 1 | 14 h 30 min |
| June | 82°F | 58°F | 70.0°F | 4.62 | – | 7 | <1 | 15 h 20 min |
| July | 86°F | 63°F | 74.5°F | 3.36 | – | 11 | <1 | 15 h |
| August | 83°F | 61°F | 72.0°F | 3.93 | – | 4 | <1 | 14 h |
| September | 77°F | 51°F | 64.1°F | 2.99 | – | 3 | <1 | 12 h 30 min |
| October | 64°F | 37°F | 50.6°F | 2.38 | – | <1 | 11 | 11 h 10 min |
| November | 47°F | 24°F | 35.8°F | 1.36 | – | <1 | 24 | 9 h 50 min |
| December | 34°F | 14°F | 23.8°F | 0.97 | – | <1 | 30 | 9 h 10 min |
| Year (annual) | 60°F | 36°F | 48.0°F | 30.28 | – | 27 | 160 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −13°C | −7.1°C | 17 mm |
| February | 1°C | −11°C | −4.7°C | 22 mm |
| March | 9°C | −5°C | 2.0°C | 41 mm |
| April | 16°C | 2°C | 8.7°C | 78 mm |
| May | 22°C | 8°C | 15.2°C | 113 mm |
| June | 28°C | 14°C | 21.1°C | 117 mm |
| July | 30°C | 17°C | 23.6°C | 85 mm |
| August | 28°C | 16°C | 22.2°C | 100 mm |
| September | 25°C | 11°C | 17.8°C | 76 mm |
| October | 18°C | 3°C | 10.3°C | 60 mm |
| November | 8°C | −4°C | 2.1°C | 35 mm |
| December | 1°C | −10°C | −4.6°C | 25 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Sioux City (0 miles away), gets 36 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137702; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Sioux City Ang?
Normal highs sit between 65°F and 85°F in May, June, August and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137702.
When is the last frost at Sioux City Ang?
In Sioux City Ang, the last spring frost (32°F) comes after April 29 in half of years and after May 11 in one year in ten; the first autumn frost comes before October 7 in half of years and before September 24 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 291 year in 10 after May 11; 9 in 10 after April 15
- First autumn frost, half of years before
- October 71 year in 10 before September 24; 9 in 10 before October 21
NOAA puts the median frost-free season at 161 days, and the season without a hard freeze (28°F) at 180 days.
A hard freeze (28°F) comes after April 19 in half of springs and before October 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sioux City Ang in zone 5a in ZIP code 51111, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 5b: the coldest night of a typical year reaches −15°F (15 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00137702; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Sioux City Ang?
In a normal year in Sioux City Ang, 27 days a year reach 90°F (1 of them 100°F or more) and 160 nights fall to 32°F or colder.
- Days at 90°F or more
- 27a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 160a normal year
- Days that stay below freezing
- 51high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00137702.
How sunny is it at Sioux City Ang?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds at Sioux City Ang, 4.2 kWh per square metre a day. July is the sunniest month (84%) and December the cloudiest (69%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.0 |
| February | 77% | 3.1 |
| March | 70% | 3.8 |
| April | 71% | 5.0 |
| May | 72% | 5.8 |
| June | 79% | 6.5 |
| July | 84% | 6.6 |
| August | 81% | 5.6 |
| September | 80% | 4.5 |
| October | 75% | 3.1 |
| November | 75% | 2.2 |
| December | 69% | 1.6 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Sioux City Ang record?
A normal year at Sioux City Ang brings 6,998 heating degree days, 30% more than the median U.S. place (5,373), and 850 cooling degree days, 6% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,042 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,419 | 0 |
| February | 1,160 | 0 |
| March | 911 | 1 |
| April | 521 | 3 |
| May | 220 | 48 |
| June | 29 | 179 |
| July | 3 | 298 |
| August | 11 | 226 |
| September | 114 | 87 |
| October | 457 | 9 |
| November | 876 | 0 |
| December | 1,277 | 0 |
| Year (annual) | 6,998 | 850 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137702. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Sioux City Ang been warmer than normal?
2025 averaged 49.6°F, 1.6°F above the 1991-2020 normal of 48.0°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.1°F | +2.1°F | 23.85 |
| 2022 | 48.1°F | +0.1°F | 14.98 |
| 2023 | 49.9°F | +1.9°F | 26.95 |
| 2024 | 50.8°F | +2.8°F | 32.09 |
| 2025 | 49.6°F | +1.6°F | 27.64 |
Over 133 complete years from 1891 to 2025, the station's annual mean temperature rose at a fitted 3.5°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00137702; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sioux City Ang's climate compare?
Sioux City Ang is warmer than 64 of the 132 places with their own NOAA record in Iowa, and wetter than 11. Across the 7,247 U.S. stations with normals, its annual mean of 48.0°F is warmer than 32%.
In the Köppen classification computed from these normals, Sioux City Ang is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Sioux City Ang share this climate record?
11 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- South Sioux City, NE13,910 people · 5 mi N
- Sergeant Bluff, IA5,335 people · 1 mi E
- Dakota Dunes, SD4,129 people · 8 mi NW
- North Sioux City, SD3,059 people · 11 mi NW
- Dakota City, NE2,047 people · 3 mi NW
- Moville, IA1,707 people · 17 mi E
- Lawton, IA949 people · 11 mi NE
- Jefferson, SD449 people · 17 mi NW
- Bronson, IA294 people · 9 mi E
- Jackson, NE215 people · 11 mi W
- Waterbury, NE70 people · 19 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Sioux City Ang's climate
What is the coldest month at Sioux City Ang?
January, with a normal high of 30°F and a normal low of 9°F. The warmest is July (86°F by day, 63°F at night).
Does it snow at Sioux City Ang?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Sioux City (0 miles away), records 36 inches of snow in a normal year.
What is the rainiest month at Sioux City Ang?
June, with 4.62 in of precipitation in a normal year; the driest is January with 0.66 in.
What plant hardiness zone is Sioux City Ang in?
The USDA's 2023 map puts Sioux City Ang in zone 5a in ZIP code 51111, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −15°F (15 years, 1991-2020): zone 5b.
How late can frost come at Sioux City Ang?
In half of years the last 32°F night comes after April 29; in one year in ten it comes after May 11. Waiting until May 11 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Sioux City, IA1 miles from this station, 48.5°F a year
- Walthill, NE17 miles from this station, 49.0°F a year
- Onawa, IA26 miles from this station, 48.5°F a year
- Wakefield, NE27 miles from this station, 48.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made