Sibley, Iowa climate: Normal weather by month, frost dates and records
Sibley's normal year runs from 5°F January nights to 82°F July afternoons, with 30.2 inches of precipitation and 42 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.9°C, January lows of −15°C, July highs of 28°C, 768 mm of precipitation a year.
- NOAA stationSibley
- Station IDUSC00137664
- Location43.40°N 95.75°W
- Elevation1,529 ft (466 m)
- From the centerunder 1 mile
- Population2,787
On October 23, the normal high in Sibley is 56°F and the normal low 33°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 Sibley.
- Jan 23° 5°
- Feb 28° 9°
- Mar 41° 21°
- Apr 56° 33°
- May 69° 46°
- Jun 79° 57°
- Jul 82° 60°
- Aug 80° 58°
- Sep 74° 49°
- Oct 60° 36°
- Nov 43° 22°
- Dec 28° 11°
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 Sibley each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 5°F. The most precipitation falls in June (4.88 in), the least in January (0.74 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 23°F | 5°F | 13.9°F | 0.74 | 8.1 | 6 | <1 | 31 | 9 h 20 min |
| February | 28°F | 9°F | 18.4°F | 0.84 | 7.4 | 5 | <1 | 28 | 10 h 30 min |
| March | 41°F | 21°F | 30.8°F | 1.59 | 7.0 | 6 | <1 | 27 | 11 h 50 min |
| April | 56°F | 33°F | 44.3°F | 3.25 | 3.7 | 10 | <1 | 15 | 13 h 20 min |
| May | 69°F | 46°F | 57.2°F | 4.06 | 0.0 | 13 | 1 | 2 | 14 h 40 min |
| June | 79°F | 57°F | 67.8°F | 4.88 | 0.0 | 12 | 3 | <1 | 15 h 20 min |
| July | 82°F | 60°F | 71.2°F | 3.30 | 0.0 | 9 | 4 | <1 | 15 h 10 min |
| August | 80°F | 58°F | 68.9°F | 3.58 | 0.0 | 9 | 2 | <1 | 14 h |
| September | 74°F | 49°F | 61.4°F | 3.25 | 0.0 | 8 | 1 | 1 | 12 h 30 min |
| October | 60°F | 36°F | 47.7°F | 2.31 | 1.1 | 8 | <1 | 12 | 11 h 10 min |
| November | 43°F | 22°F | 32.4°F | 1.38 | 5.1 | 5 | <1 | 25 | 9 h 40 min |
| December | 28°F | 11°F | 19.5°F | 1.05 | 9.1 | 6 | <1 | 31 | 9 h |
| Year (annual) | 55°F | 34°F | 44.5°F | 30.23 | 41.5 | 97 | 10 | 173 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −5°C | −15°C | −10.1°C | 19 mm | 21 cm |
| February | −2°C | −13°C | −7.6°C | 21 mm | 19 cm |
| March | 5°C | −6°C | −0.7°C | 40 mm | 18 cm |
| April | 13°C | 0°C | 6.8°C | 83 mm | 9 cm |
| May | 20°C | 8°C | 14.0°C | 103 mm | 0 cm |
| June | 26°C | 14°C | 19.9°C | 124 mm | 0 cm |
| July | 28°C | 16°C | 21.8°C | 84 mm | 0 cm |
| August | 27°C | 14°C | 20.5°C | 91 mm | 0 cm |
| September | 23°C | 10°C | 16.3°C | 83 mm | 0 cm |
| October | 15°C | 2°C | 8.7°C | 59 mm | 3 cm |
| November | 6°C | −5°C | 0.2°C | 35 mm | 13 cm |
| December | −2°C | −12°C | −6.9°C | 27 mm | 23 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137664; 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 Sibley?
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 USC00137664.
When is the last frost in Sibley?
In Sibley, the last spring frost (32°F) comes after May 5 in half of years and after May 17 in one year in ten; the first autumn frost comes before October 3 in half of years and before September 21 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
- May 51 year in 10 after May 17; 9 in 10 after April 22
- First autumn frost, half of years before
- October 31 year in 10 before September 21; 9 in 10 before October 17
NOAA puts the median frost-free season at 152 days, and the season without a hard freeze (28°F) at 171 days.
A hard freeze (28°F) comes after April 25 in half of springs and before October 13 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sibley in zone 4b in ZIP code 51249, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Sibley's NOAA station is in zone 4b: the coldest night of a typical year reaches −21°F (24 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 USC00137664; 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 Sibley?
In a normal year in Sibley, 10 days a year reach 90°F, 173 nights fall to 32°F or colder and 97 days bring measurable precipitation.
- Days at 90°F or more
- 10a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 173a normal year
- Days that stay below freezing
- 80high of 32°F or less
- Days with 0.01 inch of precipitation
- 97a normal year
- Days with 1 inch of snow or more
- 15a normal year
The highest temperature in this station's record (since 1893) is 108°F, on July 17, 1936; the lowest is −40°F, on January 12, 1912.
The wettest calendar year on that record is 2018, with 53.77 in; the snowiest season is 1982–83, with 80.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00137664; records: ACIS (NOAA Regional Climate Centers), station USC00137664. Records use complete months only; a month missing more than three days is left out.
How sunny is Sibley?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sibley, 4.1 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 | 74% | 2.0 |
| February | 79% | 3.1 |
| March | 72% | 3.9 |
| April | 70% | 4.9 |
| May | 70% | 5.6 |
| June | 76% | 6.3 |
| July | 84% | 6.6 |
| August | 81% | 5.5 |
| September | 79% | 4.4 |
| October | 73% | 3.0 |
| November | 72% | 2.0 |
| 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 much heating and cooling does Sibley need?
A normal year in Sibley brings 8,036 heating degree days, 50% more than the median U.S. place (5,373), and 592 cooling degree days, 35% 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 2,569 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,584 | 0 |
| February | 1,305 | 0 |
| March | 1,060 | 0 |
| April | 623 | 2 |
| May | 278 | 34 |
| June | 52 | 136 |
| July | 15 | 207 |
| August | 27 | 148 |
| September | 166 | 59 |
| October | 540 | 6 |
| November | 977 | 0 |
| December | 1,410 | 0 |
| Year (annual) | 8,036 | 592 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00137664. 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 Sibley been warmer than normal lately?
2025 averaged 46.6°F, 2.1°F above the 1991-2020 normal of 44.5°F. 4 of the 4 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2022 | 44.6°F | +0.1°F | 22.88 | 34.5 |
| 2023 | 46.8°F | +2.3°F | 26.87 | 37.7 |
| 2024 | 48.5°F | +4.0°F | 40.84 | 22.8 |
| 2025 | 46.6°F | +2.1°F | 28.70 | 29.2 |
Over 81 complete years from 1894 to 2025, the station's annual mean temperature rose at a fitted 3.0°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 USC00137664; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Sibley's climate compare?
Sibley is warmer than 2 of the other 131 places with their own NOAA record in Iowa, and wetter than 10. Across the 7,247 U.S. stations with normals, its annual mean of 44.5°F is warmer than 17%.
In the Köppen classification computed from these normals, Sibley is Dfb: continental, no dry season, warm 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 Sibley share this climate record?
5 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.
- Adrian, MN1,198 people · 18 mi NW
- Little Rock, IA447 people · 7 mi NW
- Ashton, IA434 people · 7 mi S
- Rushmore, MN364 people · 15 mi N
- Bigelow, MN220 people · 8 mi NE
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 Sibley's climate
What is the coldest month in Sibley?
January, with a normal high of 23°F and a normal low of 5°F. The warmest is July (82°F by day, 60°F at night).
Does it snow in Sibley?
Yes: 42 inches in a normal year, falling on 22 days with 0.1 inch or more, the most in December (9.1 inches).
What is the rainiest month in Sibley?
June, with 4.88 in of precipitation in a normal year; the driest is January with 0.74 in.
What plant hardiness zone is Sibley in?
The USDA's 2023 map puts Sibley in zone 4b in ZIP code 51249, the nearest ZIP area. By the same method at Sibley's NOAA station, the coldest night of a typical year reaches −21°F (24 years, 1991-2020): zone 4b.
How late can frost come in Sibley?
In half of years the last 32°F night comes after May 5; in one year in ten it comes after May 17. Waiting until May 17 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Iowa climateThe statewide normals and every place in the state
- Sanborn, IA16 miles from this station, 45.3°F a year
- Sheldon, IA16 miles from this station, 44.9°F a year
- Worthington, MN19 miles from this station, 44.4°F a year
- Rock Rapids, IA21 miles from this station, 46.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made