Mason City, Nebraska climate: Normal weather by month, frost dates and records
Mason City's normal year runs from 13°F January nights to 87°F July afternoons, with 26.3 inches of precipitation and 26 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.7°C, January lows of −10°C, July highs of 31°C, 668 mm of precipitation a year.
- NOAA stationMason City
- Station IDUSC00255250
- Location41.22°N 99.29°W
- Elevation2,292 ft (699 m)
- Population147
On October 23, the normal high in Mason City is 61°F and the normal low 33°F, and the chance of measurable rain or snow is 15%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mason City.
- Jan 37° 13°
- Feb 40° 16°
- Mar 52° 25°
- Apr 62° 35°
- May 71° 47°
- Jun 82° 58°
- Jul 87° 63°
- Aug 85° 60°
- Sep 78° 50°
- Oct 65° 36°
- Nov 50° 24°
- Dec 39° 16°
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 Mason City each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 13°F. The most precipitation falls in May (4.37 in), the least in January (0.60 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 37°F | 13°F | 25.0°F | 0.60 | 6.8 | 3 | <1 | 31 | 9 h 30 min |
| February | 40°F | 16°F | 28.0°F | 0.73 | 6.1 | 4 | <1 | 27 | 10 h 40 min |
| March | 52°F | 25°F | 38.6°F | 1.51 | 3.7 | 6 | <1 | 24 | 11 h 50 min |
| April | 62°F | 35°F | 48.2°F | 2.79 | 1.2 | 8 | <1 | 13 | 13 h 20 min |
| May | 71°F | 47°F | 58.7°F | 4.37 | 0.0 | 9 | 1 | 2 | 14 h 30 min |
| June | 82°F | 58°F | 69.7°F | 3.93 | 0.0 | 10 | 6 | <1 | 15 h 10 min |
| July | 87°F | 63°F | 74.8°F | 3.23 | 0.0 | 8 | 12 | <1 | 14 h 50 min |
| August | 85°F | 60°F | 72.6°F | 3.14 | 0.0 | 7 | 10 | <1 | 13 h 50 min |
| September | 78°F | 50°F | 63.8°F | 2.33 | 0.0 | 5 | 4 | 2 | 12 h 30 min |
| October | 65°F | 36°F | 50.2°F | 1.96 | 1.7 | 5 | <1 | 11 | 11 h 10 min |
| November | 50°F | 24°F | 37.3°F | 1.09 | 1.6 | 4 | <1 | 26 | 9 h 50 min |
| December | 39°F | 16°F | 27.5°F | 0.60 | 4.8 | 3 | <1 | 31 | 9 h 10 min |
| Year (annual) | 62°F | 37°F | 49.5°F | 26.28 | 25.9 | 72 | 34 | 166 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −10°C | −3.9°C | 15 mm | 17 cm |
| February | 5°C | −9°C | −2.2°C | 19 mm | 15 cm |
| March | 11°C | −4°C | 3.7°C | 38 mm | 9 cm |
| April | 16°C | 2°C | 9.0°C | 71 mm | 3 cm |
| May | 22°C | 8°C | 14.8°C | 111 mm | 0 cm |
| June | 28°C | 14°C | 20.9°C | 100 mm | 0 cm |
| July | 31°C | 17°C | 23.8°C | 82 mm | 0 cm |
| August | 30°C | 16°C | 22.6°C | 80 mm | 0 cm |
| September | 26°C | 10°C | 17.7°C | 59 mm | 0 cm |
| October | 18°C | 2°C | 10.1°C | 50 mm | 4 cm |
| November | 10°C | −4°C | 2.9°C | 28 mm | 4 cm |
| December | 4°C | −9°C | −2.5°C | 15 mm | 12 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00255250; 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 Mason City?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (5).
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 USC00255250.
When is the last frost in Mason City?
In Mason City, the last spring frost (32°F) comes after May 3 in half of years and after May 18 in one year in ten; the first autumn frost comes before October 5 in half of years and before September 23 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 31 year in 10 after May 18; 9 in 10 after April 21
- First autumn frost, half of years before
- October 51 year in 10 before September 23; 9 in 10 before October 16
NOAA puts the median frost-free season at 153 days, and the season without a hard freeze (28°F) at 172 days.
A hard freeze (28°F) comes after April 24 in half of springs and before October 15 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mason City in zone 5b in ZIP code 68855, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Mason City's NOAA station is in zone 5b: the coldest night of a typical year reaches −15°F (20 complete years).
Frost dates for every NOAA station in Nebraska · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00255250; 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 Mason City?
In a normal year in Mason City, 34 days a year reach 90°F (3 of them 100°F or more), 166 nights fall to 32°F or colder and 72 days bring measurable precipitation.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 166a normal year
- Days that stay below freezing
- 38high of 32°F or less
- Days with 0.01 inch of precipitation
- 72a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1893) is 108°F, on July 19, 2006; the lowest is −36°F, on February 11, 1899.
The wettest calendar year on that record is 1993, with 34.77 in; the snowiest season is 2009–10, with 59.2 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00255250; records: ACIS (NOAA Regional Climate Centers), station USC00255250. Records use complete months only; a month missing more than three days is left out.
How sunny is Mason City?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Mason City, 4.4 kWh per square metre a day. July is the sunniest month (86%) and March the cloudiest (73%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 76% | 2.2 |
| February | 76% | 3.1 |
| March | 73% | 4.1 |
| April | 73% | 5.3 |
| May | 74% | 6.0 |
| June | 83% | 6.9 |
| July | 86% | 6.9 |
| August | 84% | 5.9 |
| September | 82% | 4.8 |
| October | 78% | 3.4 |
| November | 78% | 2.4 |
| December | 75% | 1.9 |
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 Mason City need?
A normal year in Mason City brings 6,477 heating degree days, 21% more than the median U.S. place (5,373), and 875 cooling degree days, 4% 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 3,041 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,240 | 0 |
| February | 1,036 | 0 |
| March | 820 | 0 |
| April | 506 | 4 |
| May | 235 | 39 |
| June | 39 | 179 |
| July | 6 | 310 |
| August | 13 | 249 |
| September | 124 | 88 |
| October | 464 | 6 |
| November | 831 | 0 |
| December | 1,162 | 0 |
| Year (annual) | 6,477 | 875 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00255250. 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.
How does Mason City's climate compare?
Mason City is warmer than 58 of the other 136 places with their own NOAA record in Nebraska, and wetter than 59. Across the 7,247 U.S. stations with normals, its annual mean of 49.5°F is warmer than 38%.
In the Köppen classification computed from these normals, Mason City 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 Mason City share this climate record?
4 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.
- Ansley, NE460 people · 6 mi NW
- Litchfield, NE215 people · 9 mi SE
- Miller, NE129 people · 21 mi S
- Westerville, NE17 people · 13 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 Mason City's climate
What is the coldest month in Mason City?
January, with a normal high of 37°F and a normal low of 13°F. The warmest is July (87°F by day, 63°F at night).
Does it snow in Mason City?
Yes: 26 inches in a normal year, falling on 12 days with 0.1 inch or more, the most in January (6.8 inches).
What is the rainiest month in Mason City?
May, with 4.37 in of precipitation in a normal year; the driest is January with 0.60 in.
What plant hardiness zone is Mason City in?
The USDA's 2023 map puts Mason City in zone 5b in ZIP code 68855, the nearest ZIP area. By the same method at Mason City's NOAA station, the coldest night of a typical year reaches −15°F (20 years, 1991-2020): zone 5b.
How late can frost come in Mason City?
In half of years the last 32°F night comes after May 3; in one year in ten it comes after May 18. Waiting until May 18 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Nebraska climateThe statewide normals and every place in the state
- Loup City, NE17 miles from this station, 50.1°F a year
- Broken Bow, NE23 miles from this station, 50.2°F a year
- Ravenna, NE24 miles from this station, 49.6°F a year
- Comstock, NE24 miles from this station, 48.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made