Climate Comfort Score
68/100
Good
NOAA 1991–2020 normals 52°F annual avg Public-domain federal data
Mason City, IL Climate
Temperature, precipitation, and comfort score from NOAA NCEI 1991–2020 normals →
- 52°F
- Avg annual temp
- 68/100
- Comfort score
- 39.3"
- Annual precip
- 184d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for Mason City
Mason City, Illinois averages 52°F a year and scores 68/100 on the comfort index - good, milder than 58% of U.S. cities.
- 52°F
- average temperature, NOAA 1991-2020 normal
- 68/100
- comfort score, milder than 58% of U.S. cities
- 39.3"
- annual precipitation · 13" snow
- 184 days
- growing season, frost-free days
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
52°F (11°C)
Avg High
62°F
Avg Low
41°F
Annual Precip
39.3"
Annual Snow
12.9"
Comfort Score
68/100
Good
Avg Annual Temperature
52°F
30-year mean (NOAA NCEI)
Annual Precipitation
39.3"
Plus 12.9" of snow
Comfort score vs national 100-point ceiling (Mason City) 68.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the Mason City area.
How Mason City compares to every U.S. city
Mason City's comfort score vs. all U.S. cities
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
68 Top 42% higher than 58% of 6,915 US cities
Each bar is a band; taller bars hold more US cities. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Warming context for Mason City
MethodologyMason City's NOAA 1991-2020 normal sits inside a longer story: U.S. land temperatures have been tracking (and drifting from) the global mean since 1900, and the chart below shows that spread, with the most recent decade running warmer than the 30-year mean.
- United States land mean (NOAA NCEI) +0.11 °C/decade
- Global anomaly (NASA GISTEMP) +0.11 °C/decade
- Paris Agreement thresholds 1.5°C / 2.0°C
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 33°F (1°C) | 16°F (-9°C) | 25°F (-4°C) | 2.3" | 5.5" | 28.4 | 0.0 |
| February | 38°F (3°C) | 19°F (-7°C) | 29°F (-2°C) | 2.0" | 2.8" | 23.7 | 0.0 |
| March | 51°F (10°C) | 30°F (-1°C) | 40°F (5°C) | 2.5" | 1.7" | 19.0 | 0.0 |
| April | 64°F (18°C) | 41°F (5°C) | 53°F (12°C) | 3.7" | 0.0" | 4.5 | 0.1 |
| May | 74°F (23°C) | 53°F (12°C) | 63°F (17°C) | 4.5" | 0.0" | 0.2 | 1.2 |
| June | 82°F (28°C) | 62°F (17°C) | 72°F (22°C) | 4.2" | 0.0" | 0.0 | 6.3 |
| July | 85°F (30°C) | 65°F (18°C) | 75°F (24°C) | 5.1" | 0.0" | 0.0 | 9.5 |
| August | 84°F (29°C) | 62°F (17°C) | 73°F (23°C) | 3.6" | 0.0" | 0.0 | 6.7 |
| September | 79°F (26°C) | 54°F (12°C) | 66°F (19°C) | 3.5" | 0.0" | 0.2 | 3.4 |
| October | 66°F (19°C) | 43°F (6°C) | 54°F (12°C) | 3.3" | 0.0" | 3.7 | 0.3 |
| November | 51°F (11°C) | 31°F (-1°C) | 41°F (5°C) | 2.8" | 0.3" | 16.5 | 0.0 |
| December | 38°F (3°C) | 22°F (-6°C) | 30°F (-1°C) | 1.7" | 2.6" | 25.7 | 0.0 |
Monthly Precipitation
Average monthly rainfall and snowfall
January 2.3"
Snow: 5.5"
7.6 days with precipitation
February 2.0"
Snow: 2.8"
6.7 days with precipitation
March 2.5"
Snow: 1.7"
7.9 days with precipitation
April 3.7"
11.1 days with precipitation
May 4.5"
10.9 days with precipitation
June 4.2"
9.6 days with precipitation
July 5.1"
8.7 days with precipitation
August 3.6"
7.5 days with precipitation
September 3.5"
7.2 days with precipitation
October 3.3"
8.8 days with precipitation
November 2.8"
Snow: 0.3"
6.9 days with precipitation
December 1.7"
Snow: 2.6"
6.0 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
October 18
50% probability date
Last Spring Freeze
April 17
50% probability date
Growing Season
184 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,821
Higher = more heating needed
Cooling Degree Days
1,006
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
What Mason City's climate means for you
Mason City runs 52°F a year - peaking in July, coldest in January.
- Gardeners get about 184 frost-free days, with the last spring freeze near April 17 - plan the planting calendar around it, not the regional average.
- Energy bills track 5,821 heating and 1,006 cooling degree days a year, higher means the furnace or AC runs more.
- Comparing places to live? Line this city up against nearby cities and the national rankings. See rankings
These are 30-year NOAA normals (1991–2020) - the typical year, not a forecast for any specific season.
Climate Guides
Climate Insight: Mason City, IL
The NOAA 1991–2020 climate normals describe Mason City, Illinois as a location with an annual average temperature of 52°F, ranging from a mean daily high of 62°F to a mean daily low of 41°F. July is typically the warmest month of the year, while January is the coldest. These thirty-year averages, computed from station USC00115413, smooth out year-to-year variability and give a baseline expectation for typical conditions in any given month.
Mason City averages 39.3 inches of precipitation a year, with 12.9 inches typically falling as snow, and that matters as much to daily life here as temperature does. The frost-free season averages 184 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 17 and the first fall freeze near October 18. As for energy demand, 5,821 heating degree days and 1,006 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Mason City scores 68/100 (Good), a blended measure that weighs temperature mildness, precipitation moderation, and extreme-weather frequency against one another. Shoulder seasons bring the mildest highs and lows in the monthly tables above, summer brings July-driven heat, and winter brings January-driven cold - use that rhythm for planning. These figures are thirty-year averages rather than forecasts, so a specific year may still run warmer, cooler, wetter, or drier than what's shown.
Frequently Asked Questions
What is the average temperature in Mason City, IL? ▼
The average annual temperature in Mason City, Illinois is 52°F. The warmest month averages 85°F (30°C) and the coldest averages 16°F (-9°C).
How much rain does Mason City get? ▼
Mason City receives 39.3 inches of precipitation annually, including 12.9 inches of snow. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Mason City? ▼
Mason City has a climate comfort score of 68/100 (Good), milder than 58% of U.S. cities in the PlainClimate database.
When is the growing season in Mason City? ▼
Mason City has approximately 184 frost-free days per year, with the last spring freeze around April 17 and the first fall freeze around October 18.
How much energy does heating and cooling require in Mason City? ▼
Mason City has 5,821 heating degree days and 1,006 cooling degree days annually, a heating-dominated climate. See our <a href="/guides/reading-weather-data/" class="underline hover:text-brand-600">guide to reading weather data</a> for what these figures mean.
Where does this Mason City climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00115413 near Mason City.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00115413. For informational purposes only.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainClimate Editorial
Every figure on PlainClimate is rendered directly from NOAA 1991-2020 U.S. Climate Normals data, no number is typed in by an editor. This page draws directly on NOAA 1991-2020 U.S. Climate Normals data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.