Climate Comfort Score
68/100
Good
NOAA 1991–2020 normals 54°F annual avg Public-domain federal data
Vandalia, IL Climate
Annual temperature, rainfall, and a comfort score, sourced from NOAA NCEI's 1991–2020 normals →
- 54°F
- Avg annual temp
- 68/100
- Comfort score
- 43.7"
- Annual precip
- 197d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for Vandalia
Vandalia, Illinois averages 54°F a year and scores 68/100 on the comfort index - good, milder than 58% of U.S. cities.
- 54°F
- yearly average temperature, NOAA normal
- 68/100
- comfort score, milder than 58% of U.S. cities
- 43.7"
- precipitation, annual total
- 197 days
- frost-free days per growing season
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
54°F (12°C)
Avg High
64°F
Avg Low
44°F
Annual Precip
43.7"
Comfort Score
68/100
Good
Avg Annual Temperature
54°F
30-year mean (NOAA NCEI)
Annual Precipitation
43.7"
Liquid-equivalent total
Comfort score vs national 100-point ceiling (Vandalia) 68.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Good for the Vandalia area.
How Vandalia compares to every U.S. city
Vandalia'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 Vandalia
MethodologyZooming out from Vandalia's own normal, the chart below shows how the U.S. land temperature anomaly has tracked the global mean since 1900 - the most recent decade sits warmer than the 30-year mean shown here.
- 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 | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 37°F (3°C) | 21°F (-6°C) | 29°F (-2°C) | 3.0" | 26.0 | 0.0 |
| February | 42°F (5°C) | 24°F (-4°C) | 33°F (1°C) | 2.5" | 22.0 | 0.0 |
| March | 53°F (12°C) | 33°F (1°C) | 43°F (6°C) | 3.3" | 15.6 | 0.0 |
| April | 65°F (18°C) | 43°F (6°C) | 54°F (12°C) | 4.9" | 3.8 | 0.0 |
| May | 75°F (24°C) | 54°F (12°C) | 65°F (18°C) | 5.3" | 0.0 | 1.0 |
| June | 84°F (29°C) | 63°F (17°C) | 74°F (23°C) | 4.9" | 0.0 | 6.7 |
| July | 87°F (30°C) | 67°F (19°C) | 77°F (25°C) | 3.9" | 0.0 | 11.1 |
| August | 86°F (30°C) | 64°F (18°C) | 75°F (24°C) | 3.2" | 0.0 | 9.0 |
| September | 80°F (26°C) | 56°F (13°C) | 68°F (20°C) | 3.1" | 0.0 | 2.8 |
| October | 68°F (20°C) | 44°F (7°C) | 56°F (13°C) | 3.3" | 3.2 | 0.2 |
| November | 54°F (12°C) | 34°F (1°C) | 44°F (7°C) | 3.8" | 13.3 | 0.0 |
| December | 42°F (5°C) | 26°F (-4°C) | 34°F (1°C) | 2.7" | 24.6 | 0.0 |
Monthly Precipitation
Average monthly rainfall
January 3.0"
8.9 days with precipitation
February 2.5"
7.2 days with precipitation
March 3.3"
9.5 days with precipitation
April 4.9"
11.0 days with precipitation
May 5.3"
12.4 days with precipitation
June 4.9"
9.9 days with precipitation
July 3.9"
8.0 days with precipitation
August 3.2"
7.4 days with precipitation
September 3.1"
6.8 days with precipitation
October 3.3"
8.2 days with precipitation
November 3.8"
9.2 days with precipitation
December 2.7"
8.3 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
October 24
50% probability date
Last Spring Freeze
April 10
50% probability date
Growing Season
197 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,140
Higher = more heating needed
Cooling Degree Days
1,222
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
What Vandalia's climate means for you
Vandalia runs 54°F a year - peaking in July, coldest in January.
- Gardeners get about 197 frost-free days, with the last spring freeze near April 10 - plan the planting calendar around it, not the regional average.
- Energy bills track 5,140 heating and 1,222 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: Vandalia, IL
Vandalia, Illinois runs an annual average of 54°F, ranging from a mean daily high of 64°F to a mean daily low of 44°F, per NOAA's 1991–2020 climate normals. July is typically the warmest month of the year, while January is the coldest. Drawn from station USC00118781, these thirty-year averages smooth out year-to-year swings into a baseline for what a typical month looks like here.
Beyond temperature, Vandalia averages 43.7 inches of precipitation annually, predominantly as rainfall - a real factor for anyone planning to live, garden, or travel here. The frost-free season averages 197 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 10 and the first fall freeze near October 24. Turning to energy use, 5,140 heating degree days and 1,222 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Vandalia 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 Vandalia, IL? ▼
The average annual temperature in Vandalia, Illinois is 54°F. The warmest month averages 87°F (30°C) and the coldest averages 21°F (-6°C).
How much rain does Vandalia get? ▼
Vandalia receives 43.7 inches of precipitation annually. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Vandalia? ▼
Vandalia 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 Vandalia? ▼
Vandalia has approximately 197 frost-free days per year, with the last spring freeze around April 10 and the first fall freeze around October 24.
How much energy does heating and cooling require in Vandalia? ▼
Vandalia has 5,140 heating degree days and 1,222 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 Vandalia climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00118781 near Vandalia.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00118781. 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.