Hennepin, IL Climate: Temperature & Rain by Month
Annual temperature and rainfall from NOAA NCEI's 1991–2020 normals →; comfort score computed by PlainClimate
30-year climate normals (1991-2020) from Hennepin's primary NOAA station, HENNEPIN.
The climate verdict for Hennepin
Hennepin, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 51°F. Its climate comfort score of 68/100 (good) lands mid-pack nationally, exceeding 56% of station-mapped location scores.
- 51°F
- annual average temperature (NOAA normal)
- 68/100
- comfort score, above 56% of station-mapped location scores
- 38.6"
- annual precipitation
- 187 days
- frost-free days per growing season
Hennepin: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00114012 · Hennepin, IL 51°F mean · 38.6" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 51°F
- RANK-MID #3,156
- PHOTO-FINISH ≈ Detroit Willow…
- PRCP-MID 38.6"
- SWING-WIDE 50°F
- COMF-MID 68/100
- LOAD-HEAT 5,869 HDD
- STN-1 USC00114012
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Detroit Willow Run, MI (+ 0 °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.
- Hennepin (this station) 51°F
- Hot Burlington Cars…, CO 51°F
- Near Detroit Willow…, MI 51°F
- Near Partoun, UT 51°F
- Near Paris Stp, IL 51°F
Climate Living Index · Hennepin
Hennepin: 61/100 · grade C
Hennepin publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Hennepin, not an official NOAA rating. Rankings still use Comfort Score 68/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 38.6 in · 3.6 from 35 in | 87/100 · A |
| Normal heat + freeze calendar | 125 calendar days | 62/100 · C |
| Frost-free season | 187 days/year | 55/100 · C |
| Annual temperature balance | 51.4°F · 16.1° from 67.5°F | 46/100 · D |
Hennepin · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Hennepin is a continental Köppen climate: Dfa
Coldest-month mean 24.6°F and warmest-month mean 74.5°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
- 74.5°F
- Coldest month
- 24.6°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 Hennepin sits across the climate record
Three NOAA fields for Hennepin's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 46th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 55th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 80%
- Warmest-to-coldest month gap for Hennepin is large versus 6,861 complete station-years.
How Hennepin compares across U.S. station-mapped locations
Hennepin's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
68 Top 44% score exceeds 56% 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%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). This entry sits in this band.
- 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
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 32°F (0°C) | 17°F (-8°C) | 25°F (-4°C) | 1.9" | 27.8 | 0.0 |
| February | 37°F (3°C) | 20°F (-7°C) | 29°F (-2°C) | 1.8" | 24.0 | 0.0 |
| March | 50°F (10°C) | 30°F (-1°C) | 40°F (5°C) | 2.5" | 18.1 | 0.0 |
| April | 64°F (18°C) | 41°F (5°C) | 52°F (11°C) | 3.9" | 5.7 | 0.0 |
| May | 74°F (23°C) | 51°F (11°C) | 63°F (17°C) | 4.8" | 0.1 | 0.8 |
| June | 82°F (28°C) | 61°F (16°C) | 72°F (22°C) | 4.5" | 0.0 | 3.3 |
| July | 85°F (29°C) | 65°F (18°C) | 75°F (24°C) | 3.9" | 0.0 | 6.3 |
| August | 83°F (28°C) | 62°F (17°C) | 73°F (23°C) | 3.8" | 0.0 | 3.4 |
| September | 77°F (25°C) | 55°F (13°C) | 66°F (19°C) | 3.5" | 0.0 | 2.8 |
| October | 65°F (18°C) | 43°F (6°C) | 54°F (12°C) | 3.3" | 3.1 | 0.0 |
| November | 50°F (10°C) | 32°F (0°C) | 41°F (5°C) | 2.6" | 16.0 | 0.0 |
| December | 37°F (3°C) | 22°F (-6°C) | 29°F (-1°C) | 2.2" | 24.2 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 15, short of 90°F on every date, while 125 dates carry a normal low at or below freezing, the coldest 16°F near January 16.
The freezing stretch
The normal low stays at or below 32°F into March 20, then returns to freezing around November 17, covering 125 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.
The widest day
September 29 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 Hennepin.
Monthly Precipitation
Average monthly rainfall
Hennepin spreads its precipitation across the year
Neither half of the year dominates here: June through August take 32% of the annual total and December through February 15%, with neither reaching the 35% that would mark a distinct wet season. Hennepin has no dry season to plan around, though it does carry a wide 49.9°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 4.8" and February 1.8". The three wettest months together take 34% 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.
Frost Dates & Growing Season
First Fall Freeze
October 22
50% probability date
Last Spring Freeze
April 18
50% probability date
Growing Season
187 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,869
Higher = more heating needed
Cooling Degree Days
946
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Hennepin 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 (51°F here).
- Aberdeen, WA 51°F · 0.0°F off
- Astoria, OR 51°F · 0.0°F off
- Beatrice, NE 51°F · 0.0°F off
- Brockton, MA 51°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (38.6" here), excluding temperature-peer places.
- Calistoga, CA 38.6" · 0.0" off
- Howard, KS 38.6" · 0.0" off
- Mabel, MN 38.6" · 0.0" off
- Manchester, IA 38.6" · 0.0" off
Data-derived climate profile
How Hennepin's climate pattern fits together
heating led · moderate · mid swing
Hennepin's energy balance leans toward cold weather: 5,869 annual heating degree days against 946 for cooling. Its 49.9°F seasonal range still makes the monthly rows more useful than the annual average alone.
Hennepin's frost-free season lasts about 187 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
July and January mark the typical warm and cold ends of the calendar in Hennepin's middle-range seasonal profile. The measured spread is 49.9°F. The annual average is 51°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Hennepin's 38.6 inches of annual precipitation falls in PlainClimate's middle band, so “wet” or “dry” is not the leading description. Snowfall is not added to the interpretation because its annual value is missing. Temperature balance and the calendar distribution carry more information than the annual moisture label alone.
These labels group NOAA 1991-2020 normals from Hennepin's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Hennepin, not an official NOAA class or a year-ahead forecast.
Questions about Hennepin's climate
How much rain does Hennepin get? ▼
How cold does Hennepin get in winter? ▼
How much energy does heating and cooling require in Hennepin? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Hennepin's primary station: HENNEPIN (USC00114012). 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 1734098). Match rule for Hennepin: 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 Hennepin 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.