Lisle-morton Arboretum, IL Climate: Temperature & Rain by Month
Explore NOAA NCEI's 1991–2020 climate normals → and a clearly labeled PlainClimate comfort calculation
30-year climate normals (1991-2020) from Lisle-morton Arboretum's primary NOAA station, LISLE-MORTON ARBORETUM.
The climate verdict for Lisle-morton Arboretum
Lisle-morton Arboretum, 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 64/100 (good) lands mid-pack nationally, exceeding 49% of station-mapped location scores.
- 49°F
- annual average temperature (NOAA normal)
- 64/100
- comfort score, above 49% of station-mapped location scores
- 40.2"
- annual precipitation
- 171 days
- frost-free days per growing season
Lisle-morton Arboretum: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00115097 · Lisle-morton Arboretum, IL 49°F mean · 40.2" 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 #2,470
- PHOTO-FINISH ≈ Crystal Lake
- PRCP-MID 40.2"
- SWING-WIDE 50°F
- COMF-MID 64/100
- LOAD-HEAT 6,506 HDD
- STN-1 USC00115097
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Crystal Lake, IL ( -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.
- Lisle-morton Ar… (this station) 49°F
- Cold Crystal Lake, IL 49°F
- Near Saint Johns, MI 49°F
- Near Tully Lake, MA 49°F
- Near Scottsbluff, NE 49°F
Climate Living Index · Lisle-morton Arboretum
Lisle-morton Arboretum: 51/100 · grade D
Lisle-morton Arboretum publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Lisle-morton Arboretum, not an official NOAA rating. Rankings still use Comfort Score 64/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 40.2 in · 5.2 from 35 in | 82/100 · B |
| Normal heat + freeze calendar | 147 calendar days | 49/100 · D |
| Frost-free season | 171 days/year | 43/100 · D |
| Annual temperature balance | 49.2°F · 18.3° from 67.5°F | 37/100 · F |
Lisle-morton Arboretum · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Lisle-morton Arboretum is a continental Köppen climate: Dfa
Coldest-month mean 23.1°F and warmest-month mean 73.1°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
- 73.1°F
- Coldest month
- 23.1°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 Lisle-morton Arboretum sits across the climate record
Three NOAA fields for Lisle-morton Arboretum's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 36th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 58th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 81%
- Warmest-to-coldest month gap for Lisle-morton Arboretum is large versus 6,861 complete station-years.
How Lisle-morton Arboretum compares across U.S. station-mapped locations
Lisle-morton Arboretum's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
64 49th percentile score exceeds 49% 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) | 15°F (-10°C) | 23°F (-5°C) | 2.2" | 29.1 | 0.0 |
| February | 35°F (2°C) | 18°F (-8°C) | 26°F (-3°C) | 2.0" | 26.4 | 0.0 |
| March | 47°F (8°C) | 26°F (-3°C) | 37°F (3°C) | 2.4" | 22.9 | 0.0 |
| April | 59°F (15°C) | 36°F (2°C) | 48°F (9°C) | 3.8" | 10.6 | 0.0 |
| May | 71°F (21°C) | 47°F (9°C) | 59°F (15°C) | 4.8" | 1.1 | 1.3 |
| June | 81°F (27°C) | 58°F (14°C) | 69°F (21°C) | 4.4" | 0.0 | 3.6 |
| July | 84°F (29°C) | 62°F (17°C) | 73°F (23°C) | 4.3" | 0.0 | 6.7 |
| August | 83°F (28°C) | 60°F (16°C) | 71°F (22°C) | 4.3" | 0.0 | 3.4 |
| September | 76°F (24°C) | 52°F (11°C) | 64°F (18°C) | 3.4" | 0.1 | 2.1 |
| October | 63°F (17°C) | 40°F (5°C) | 52°F (11°C) | 3.6" | 6.8 | 0.0 |
| November | 48°F (9°C) | 30°F (-1°C) | 39°F (4°C) | 2.8" | 19.2 | 0.0 |
| December | 37°F (3°C) | 21°F (-6°C) | 29°F (-2°C) | 2.3" | 27.4 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 11, short of 90°F on every date, while 147 dates carry a normal low at or below freezing, the coldest 14°F near January 18.
The freezing stretch
The normal low stays at or below 32°F into April 3, then returns to freezing around November 9, covering 147 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 14 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 Lisle-morton Arboretum.
Monthly Precipitation
Average monthly rainfall
Lisle-morton Arboretum 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 16%, with neither reaching the 35% that would mark a distinct wet season. Lisle-morton Arboretum has no dry season to plan around, though it does carry a wide 50°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 4.8" and February 2.0". 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 16
50% probability date
Last Spring Freeze
April 28
50% probability date
Growing Season
171 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,506
Higher = more heating needed
Cooling Degree Days
775
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Lisle-morton Arboretum 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).
- Battle Creek, MI 49°F · 0.0°F off
- Beaconsfield, IA 49°F · 0.0°F off
- Black Forest, CO 49°F · 0.0°F off
- Council, ID 49°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (40.2" here), excluding temperature-peer places.
- Angelica, NY 40.2" · 0.0" off
- Lancaster, OH 40.2" · 0.0" off
- Upper Sandusky, OH 40.2" · 0.0" off
- Anamosa, IA 40.1" · 0.0" off
Data-derived climate profile
How Lisle-morton Arboretum's climate pattern fits together
heating led · moderate · mid swing
Lisle-morton Arboretum's energy balance leans toward cold weather: 6,506 annual heating degree days against 775 for cooling. Its 50.0°F seasonal range still makes the monthly rows more useful than the annual average alone.
Lisle-morton Arboretum's frost-free season lasts about 171 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 Lisle-morton Arboretum's middle-range seasonal profile. The measured spread is 50.0°F. The annual average is 49°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Lisle-morton Arboretum's 40.2 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 Lisle-morton Arboretum'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 Lisle-morton Arboretum, not an official NOAA class or a year-ahead forecast.
Questions about Lisle-morton Arboretum's climate
How much rain does Lisle-morton Arboretum get? ▼
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How much energy does heating and cooling require in Lisle-morton Arboretum? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Lisle-morton Arboretum's primary station: LISLE-MORTON ARBORETUM (USC00115097). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Lisle-morton Arboretum; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Lisle-morton Arboretum 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.