Walnut, IL Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Walnut's primary NOAA station, WALNUT.
The climate verdict for Walnut
Walnut, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 49°F. Its climate comfort score of 59/100 (moderate) lands mid-pack nationally, exceeding 37% of station-mapped location scores.
- 49°F
- average temperature, NOAA 1991-2020 normal
- 59/100
- comfort score, above 37% of station-mapped location scores
- 36.8"
- annual precipitation · 36" snow
- 173 days
- growing season, frost-free days
Walnut: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00118916 · Walnut, IL 49°F mean · 36.8" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 49°F
- RANK-COOL #2,539
- PHOTO-FINISH ≈ Corning
- PRCP-MID 36.8"
- SWING-WIDE 52°F
- COMF-MID 59/100
- LOAD-HEAT 6,510 HDD
- STN-1 USC00118916
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Corning, IA (+ 0.1 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every IL station list.
- Walnut (this station) 49°F
- Hot Dixon, IL 49°F
- Near Corning, IA 49°F
- Near Rockford Gtr Ro…, IL 49°F
- Near Lake Geneva Wwtp, WI 49°F
Climate Living Index · Walnut
Walnut: 52/100 · grade D
Walnut publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Walnut, not an official NOAA rating. Rankings still use Comfort Score 59/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 36.8 in · 1.8 from 35 in | 92/100 · A |
| Normal heat + freeze calendar | 140 calendar days | 53/100 · D |
| Frost-free season | 173 days/year | 44/100 · D |
| Annual temperature balance | 49.3°F · 18.2° from 67.5°F | 37/100 · F |
| Snowfall burden | 35.9 inches/year | 32/100 · F |
Walnut · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Walnut is a continental Köppen climate: Dfa
Coldest-month mean 21.1°F and warmest-month mean 73.4°F place this station in continental, no dry season, hot summer climates (Dfa). Class Dfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, hot summer.
- Köppen code
- Dfa
- Group
- Continental
- Warmest month
- 73.4°F
- Coldest month
- 21.1°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Walnut sits across the climate record
Three NOAA fields for Walnut's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 37th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 51st percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 87%
- Warmest-to-coldest month gap for Walnut is large versus 6,861 complete station-years.
How Walnut compares across U.S. station-mapped locations
Walnut's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
59 37th percentile score exceeds 37% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). This entry sits in this band.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Walnut's measured station temperature trend
MethodologyAcross 101 complete annual observations from 1893 to 2025, WALNUT warmed at a fitted rate of 0.09°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Walnut primary station fitted change +0.09 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 29°F (-1°C) | 13°F (-11°C) | 21°F (-6°C) | 1.5" | 12.7" | 29.6 | 0.0 |
| February | 34°F (1°C) | 17°F (-8°C) | 25°F (-4°C) | 1.7" | 8.4" | 25.5 | 0.0 |
| March | 47°F (8°C) | 28°F (-2°C) | 38°F (3°C) | 2.2" | 4.7" | 22.0 | 0.0 |
| April | 61°F (16°C) | 39°F (4°C) | 50°F (10°C) | 3.4" | 0.6" | 6.9 | 0.0 |
| May | 72°F (22°C) | 51°F (10°C) | 61°F (16°C) | 4.6" | 0.0" | 0.4 | 1.0 |
| June | 81°F (27°C) | 60°F (16°C) | 71°F (21°C) | 4.9" | 0.0" | 0.0 | 3.5 |
| July | 83°F (29°C) | 63°F (17°C) | 73°F (23°C) | 3.9" | 0.0" | 0.0 | 5.3 |
| August | 82°F (28°C) | 61°F (16°C) | 71°F (22°C) | 3.8" | 0.0" | 0.0 | 2.8 |
| September | 76°F (24°C) | 53°F (12°C) | 64°F (18°C) | 3.4" | 0.0" | 0.2 | 1.6 |
| October | 63°F (17°C) | 41°F (5°C) | 52°F (11°C) | 3.0" | 0.2" | 5.8 | 0.1 |
| November | 48°F (9°C) | 30°F (-1°C) | 39°F (4°C) | 2.3" | 2.0" | 18.3 | 0.0 |
| December | 35°F (2°C) | 19°F (-7°C) | 27°F (-3°C) | 2.0" | 7.3" | 27.5 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 84°F around July 5, short of 90°F on every date, while 140 dates carry a normal low at or below freezing, the coldest 12°F near January 20.
The freezing stretch
The normal low stays at or below 32°F into March 28, then returns to freezing around November 10, covering 140 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is May 20, when 31% of years recorded at least a hundredth of an inch. The driest is February 3 at 19%. Summed across the calendar, that is about 84 wet dates a year.
The widest day
September 25 carries the biggest normal gap between afternoon and dawn, 24°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Walnut.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 12.7"
6.3 days with precipitation
Snow: 8.4"
5.4 days with precipitation
Snow: 4.7"
6.7 days with precipitation
Snow: 0.6"
8.2 days with precipitation
9.5 days with precipitation
8.3 days with precipitation
6.8 days with precipitation
7.0 days with precipitation
6.1 days with precipitation
Snow: 0.2"
6.5 days with precipitation
Snow: 2.0"
5.8 days with precipitation
Snow: 7.3"
6.1 days with precipitation
Walnut spreads its precipitation across the year
Neither half of the year dominates here: June through August take 34% of the annual total and December through February 14%, with neither reaching the 35% that would mark a distinct wet season. Walnut has no dry season to plan around, though it does carry a wide 52.3°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: June averages 4.9" and January 1.5". The three wettest months together take 37% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
When it rains in Walnut, it arrives in quantity
36.8" of precipitation falls across only about 83 wet days here, averaging 0.45 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 83 a year, 23% of all days
- Average depth per wet day
- 0.45 inches
- Most wet days
- May, about 10
- Fewest wet days
- February, about 5
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Winter brings real snow to Walnut
Walnut averages 35.9 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 14 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 35.9 inches of depth.
- Days recording measurable snow: about 14 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 10% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
October 14
50% probability date
Last Spring Freeze
April 24
50% probability date
Growing Season
173 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,510
Higher = more heating needed
Cooling Degree Days
841
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Walnut on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (49°F here).
- Albion, NY 49°F · 0.0°F off
- Antelope, OR 49°F · 0.0°F off
- Atlantic, IA 49°F · 0.0°F off
- Fort Calhoun, NE 49°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (36.8" here), excluding temperature-peer places.
- Troy, KS 36.8" · 0.0" off
- Waverly, NY 36.8" · 0.0" off
- Richfield, WI 36.8" · 0.0" off
- Rushford, MN 36.9" · 0.0" off
Snow and freeze rhythm
When cold and snow define Walnut
heating led · moderate · mid swing
Walnut's energy balance leans toward cold weather: 6,510 annual heating degree days against 841 for cooling. Its 52.3°F seasonal range still makes the monthly rows more useful than the annual average alone.
Walnut's frost-free season lasts about 173 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Walnut coldest normal
January
Averaging 21°F (-6°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Walnut typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Walnut snow peak
January
Walnut averages 35.9 inches of snow a year, with January the snowiest month on the normals.
Questions about Walnut's climate
How much snow does Walnut get? ▼
How cold does Walnut get in winter? ▼
How much energy does heating and cooling require in Walnut? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Walnut's primary station: WALNUT (USC00118916). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 1778526). Match rule for Walnut: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Walnut comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.