Sioux Rapids, Iowa climate: Normal weather by month, frost dates and records
Sioux Rapids's normal year runs from 8°F January nights to 82°F July afternoons, with 32.0 inches of precipitation and 35 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.0°C, January lows of −13°C, July highs of 28°C, 813 mm of precipitation a year.
- NOAA stationSioux Rapids (4 mi E)
- Station IDUSC00137726
- Location42.89°N 95.07°W
- Elevation1,420 ft (433 m)
- From the center4 miles
- Population722
On October 23, the normal high in Sioux Rapids is 57°F and the normal low 35°F, and the chance of measurable rain or snow is 23%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sioux Rapids.
- Jan 25° 8°
- Feb 30° 13°
- Mar 43° 25°
- Apr 58° 36°
- May 70° 48°
- Jun 80° 59°
- Jul 82° 62°
- Aug 79° 59°
- Sep 74° 51°
- Oct 61° 39°
- Nov 44° 25°
- Dec 30° 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 in Sioux Rapids each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 8°F. The most precipitation falls in June (5.05 in), the least in January (0.62 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 25°F | 8°F | 16.7°F | 0.62 | 8.0 | 6 | <1 | 31 | 9 h 20 min |
| February | 30°F | 13°F | 21.4°F | 0.83 | 6.9 | 6 | <1 | 27 | 10 h 30 min |
| March | 43°F | 25°F | 33.9°F | 1.76 | 6.5 | 7 | <1 | 25 | 11 h 50 min |
| April | 58°F | 36°F | 47.1°F | 3.58 | 2.3 | 10 | <1 | 11 | 13 h 20 min |
| May | 70°F | 48°F | 59.1°F | 4.19 | 0.3 | 12 | 1 | 1 | 14 h 40 min |
| June | 80°F | 59°F | 69.5°F | 5.05 | 0.0 | 11 | 3 | <1 | 15 h 20 min |
| July | 82°F | 62°F | 72.1°F | 3.29 | 0.0 | 8 | 4 | <1 | 15 h |
| August | 79°F | 59°F | 69.2°F | 4.41 | 0.0 | 8 | 1 | <1 | 14 h |
| September | 74°F | 51°F | 62.4°F | 3.39 | 0.0 | 8 | 1 | 1 | 12 h 30 min |
| October | 61°F | 39°F | 49.5°F | 2.51 | 0.7 | 8 | <1 | 8 | 11 h 10 min |
| November | 44°F | 25°F | 34.5°F | 1.42 | 3.8 | 6 | <1 | 23 | 9 h 50 min |
| December | 30°F | 14°F | 21.9°F | 0.94 | 6.7 | 6 | <1 | 30 | 9 h |
| Year (annual) | 56°F | 37°F | 46.4°F | 31.99 | 35.2 | 96 | 11 | 157 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −13°C | −8.5°C | 16 mm | 20 cm |
| February | −1°C | −11°C | −5.9°C | 21 mm | 18 cm |
| March | 6°C | −4°C | 1.1°C | 45 mm | 17 cm |
| April | 15°C | 2°C | 8.4°C | 91 mm | 6 cm |
| May | 21°C | 9°C | 15.1°C | 106 mm | 1 cm |
| June | 27°C | 15°C | 20.8°C | 128 mm | 0 cm |
| July | 28°C | 17°C | 22.3°C | 84 mm | 0 cm |
| August | 26°C | 15°C | 20.7°C | 112 mm | 0 cm |
| September | 23°C | 11°C | 16.9°C | 86 mm | 0 cm |
| October | 16°C | 4°C | 9.7°C | 64 mm | 2 cm |
| November | 7°C | −4°C | 1.4°C | 36 mm | 10 cm |
| December | −1°C | −10°C | −5.6°C | 24 mm | 17 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137726; 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.
When is the best weather to visit Sioux Rapids?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (8).
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 USC00137726.
When is the last frost in Sioux Rapids?
In Sioux Rapids, the last spring frost (32°F) comes after April 30 in half of years and after May 11 in one year in ten; the first autumn frost comes before October 5 in half of years and before September 22 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 301 year in 10 after May 11; 9 in 10 after April 14
- First autumn frost, half of years before
- October 51 year in 10 before September 22; 9 in 10 before October 21
NOAA puts the median frost-free season at 159 days, and the season without a hard freeze (28°F) at 180 days.
A hard freeze (28°F) comes after April 18 in half of springs and before October 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sioux Rapids in zone 5a in ZIP code 50585, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Sioux Rapids's NOAA station is in zone 5a: the coldest night of a typical year reaches −19°F (27 complete years).
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00137726; 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 in Sioux Rapids?
In a normal year in Sioux Rapids, 11 days a year reach 90°F, 157 nights fall to 32°F or colder and 96 days bring measurable precipitation.
- Days at 90°F or more
- 11a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 157a normal year
- Days that stay below freezing
- 67high of 32°F or less
- Days with 0.01 inch of precipitation
- 96a normal year
- Days with 1 inch of snow or more
- 12a normal year
The highest temperature in this station's record (since 1941) is 107°F, on July 31, 1955; the lowest is −32°F, on January 21, 1970.
The wettest calendar year on that record is 2018, with 46.55 in; the snowiest season is 1961–62, with 67.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00137726; records: ACIS (NOAA Regional Climate Centers), station USC00137726. Records use complete months only; a month missing more than three days is left out.
How sunny is Sioux Rapids?
Over a year 76% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sioux Rapids, 4.1 kWh per square metre a day. July is the sunniest month (84%) and December the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 72% | 2.0 |
| February | 77% | 3.1 |
| March | 70% | 3.9 |
| April | 70% | 4.9 |
| May | 71% | 5.7 |
| June | 77% | 6.4 |
| July | 84% | 6.6 |
| August | 81% | 5.6 |
| September | 79% | 4.5 |
| October | 74% | 3.1 |
| November | 73% | 2.2 |
| December | 70% | 1.7 |
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 much heating and cooling does Sioux Rapids need?
A normal year in Sioux Rapids brings 7,396 heating degree days, 38% more than the median U.S. place (5,373), and 668 cooling degree days, 26% 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 2,777 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,496 | 0 |
| February | 1,222 | 0 |
| March | 965 | 1 |
| April | 541 | 4 |
| May | 227 | 44 |
| June | 31 | 166 |
| July | 8 | 227 |
| August | 22 | 154 |
| September | 145 | 66 |
| October | 488 | 8 |
| November | 915 | 0 |
| December | 1,336 | 0 |
| Year (annual) | 7,396 | 668 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137726. 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.
Has Sioux Rapids been warmer than normal lately?
2025 averaged 47.5°F, 1.1°F above the 1991-2020 normal of 46.4°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 47.5°F | +1.1°F | 30.74 | 33.8 |
| 2022 | 45.0°F | −1.4°F | 19.73 | 31.5 |
| 2023 | 47.7°F | +1.3°F | 35.77 | – |
| 2024 | 49.2°F | +2.8°F | 39.93 | – |
| 2025 | 47.5°F | +1.1°F | 33.25 | – |
Over 48 complete years from 1942 to 2025, the station's annual mean temperature rose at a fitted 3.1°F per century (+0.17°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00137726; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sioux Rapids's climate compare?
Sioux Rapids is warmer than 27 of the other 131 places with their own NOAA record in Iowa, and wetter than 15. Across the 7,247 U.S. stations with normals, its annual mean of 46.4°F is warmer than 25%.
In the Köppen classification computed from these normals, Sioux Rapids 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 Rapids share this climate record?
10 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.
- Laurens, IA1,253 people · 11 mi E
- Albert City, IA627 people · 10 mi SE
- Peterson, IA321 people · 14 mi W
- Marathon, IA221 people · 5 mi SE
- Rembrandt, IA199 people · 7 mi SW
- Linn Grove, IA155 people · 9 mi W
- Webb, IA139 people · 5 mi NE
- Greenville, IA69 people · 10 mi NW
- Rossie, IA46 people · 10 mi NW
- Gillett Grove, IA31 people · 9 mi N
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 Rapids's climate
What is the coldest month in Sioux Rapids?
January, with a normal high of 25°F and a normal low of 8°F. The warmest is July (82°F by day, 62°F at night).
Does it snow in Sioux Rapids?
Yes: 35 inches in a normal year, falling on 25 days with 0.1 inch or more, the most in January (8.0 inches).
What is the rainiest month in Sioux Rapids?
June, with 5.05 in of precipitation in a normal year; the driest is January with 0.62 in.
What plant hardiness zone is Sioux Rapids in?
The USDA's 2023 map puts Sioux Rapids in zone 5a in ZIP code 50585, the nearest ZIP area. By the same method at Sioux Rapids's NOAA station, the coldest night of a typical year reaches −19°F (27 years, 1991-2020): zone 5a.
How late can frost come in Sioux Rapids?
In half of years the last 32°F night comes after April 30; 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
- Storm Lake, IA18 miles from this station, 47.1°F a year
- Spencer, IA20 miles from this station, 46.8°F a year
- Pocahontas, IA24 miles from this station, 46.9°F a year
- Emmetsburg, IA24 miles from this station, 47.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made