Climate Comfort Score
59/100
Moderate
NOAA 1991–2020 normals 49°F annual avg Public-domain federal data
Crystal Lake, IL Climate
Explore average temperature, rainfall, and comfort score sourced from NOAA NCEI's 1991–2020 climate normals →
- 49°F
- Avg annual temp
- 59/100
- Comfort score
- 39.4"
- Annual precip
- 180d
- Growing season
30-year climate normals from 1 weather station (1991-2020).
The climate verdict for Crystal Lake
Crystal Lake, Illinois averages 49°F a year and scores 59/100 on the comfort index - moderate, milder than 39% of U.S. cities.
- 49°F
- average temperature, NOAA 1991-2020 normal
- 59/100
- comfort score, milder than 39% of U.S. cities
- 39.4"
- annual precipitation · 35" snow
- 180 days
- frost-free growing season
Based on NOAA U.S. Climate Normals (1991–2020) - 30-year averages describing the typical year, not a forecast.
Avg Temperature
49°F (10°C)
Avg High
59°F
Avg Low
39°F
Annual Precip
39.4"
Annual Snow
35.1"
Comfort Score
59/100
Moderate
Avg Annual Temperature
49°F
30-year mean (NOAA NCEI)
Annual Precipitation
39.4"
Plus 35.1" of snow
Comfort score vs national 100-point ceiling (Crystal Lake) 59.0%
National median (63)
PlainClimate composite, temperature mildness, humidity, precipitation, extreme-weather frequency. Moderate for the Crystal Lake area.
How Crystal Lake compares to every U.S. city
Crystal Lake's comfort score vs. all U.S. cities
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
59 Top 61% higher than 39% 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 Crystal Lake
MethodologyHow the U.S. land temperature anomaly tracks against the global mean since 1900. The current NOAA 1991-2020 normal for Crystal Lake captures average conditions across the spread shown, the most recent decade is 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 | 32°F (0°C) | 14°F (-10°C) | 23°F (-5°C) | 2.0" | 10.0" | 28.9 | 0.0 |
| February | 35°F (2°C) | 16°F (-9°C) | 26°F (-3°C) | 1.8" | 9.0" | 27.2 | 0.0 |
| March | 47°F (8°C) | 26°F (-3°C) | 37°F (3°C) | 2.5" | 4.4" | 22.1 | 0.0 |
| April | 59°F (15°C) | 37°F (3°C) | 48°F (9°C) | 3.8" | 1.2" | 9.1 | 0.0 |
| May | 71°F (22°C) | 48°F (9°C) | 60°F (15°C) | 5.0" | 0.0" | 0.3 | 2.1 |
| June | 80°F (27°C) | 58°F (15°C) | 69°F (21°C) | 5.3" | 0.0" | 0.0 | 5.5 |
| July | 84°F (29°C) | 63°F (17°C) | 73°F (23°C) | 3.9" | 0.0" | 0.0 | 7.7 |
| August | 82°F (28°C) | 61°F (16°C) | 72°F (22°C) | 3.8" | 0.0" | 0.0 | 4.0 |
| September | 74°F (24°C) | 52°F (11°C) | 63°F (17°C) | 3.5" | 0.0" | 0.0 | 2.5 |
| October | 62°F (17°C) | 42°F (6°C) | 52°F (11°C) | 3.2" | 0.2" | 3.4 | 0.0 |
| November | 48°F (9°C) | 31°F (-1°C) | 39°F (4°C) | 2.5" | 1.6" | 18.0 | 0.0 |
| December | 36°F (2°C) | 20°F (-6°C) | 28°F (-2°C) | 2.1" | 8.7" | 26.5 | 0.0 |
Monthly Precipitation
Average monthly rainfall and snowfall
January 2.0"
Snow: 10.0"
8.6 days with precipitation
February 1.8"
Snow: 9.0"
7.6 days with precipitation
March 2.5"
Snow: 4.4"
8.3 days with precipitation
April 3.8"
Snow: 1.2"
11.0 days with precipitation
May 5.0"
11.8 days with precipitation
June 5.3"
9.9 days with precipitation
July 3.9"
8.5 days with precipitation
August 3.8"
8.9 days with precipitation
September 3.5"
8.0 days with precipitation
October 3.2"
Snow: 0.2"
9.4 days with precipitation
November 2.5"
Snow: 1.6"
8.5 days with precipitation
December 2.1"
Snow: 8.7"
9.2 days with precipitation
Frost Dates & Growing Season
First Fall Freeze
October 22
50% probability date
Last Spring Freeze
April 25
50% probability date
Growing Season
180 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,520
Higher = more heating needed
Cooling Degree Days
771
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
What Crystal Lake's climate means for you
Crystal Lake runs 49°F a year - peaking in July, coldest in January.
- Gardeners get about 180 frost-free days, with the last spring freeze near April 25 - plan the planting calendar around it, not the regional average.
- Energy bills track 6,520 heating and 771 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: Crystal Lake, IL
An annual average temperature of 49°F, ranging from a mean daily high of 59°F to a mean daily low of 39°F is what the NOAA 1991–2020 climate normals report for Crystal Lake, Illinois. July is typically the warmest month of the year, while January is the coldest. That baseline comes from station USC00112048 and thirty years of averaging, so it reflects a typical month rather than any one year's swings.
Rainfall (and snow, where it falls) shapes day-to-day life here as much as temperature does. Crystal Lake sees about 39.4 inches of precipitation a year, with 35.1 inches typically falling as snow. The frost-free season averages 180 days, which directly shapes the planting calendar and growing potential for the area, with the last spring freeze near April 25 and the first fall freeze near October 22. On the energy side, 6,520 heating degree days and 771 cooling degree days tell the story of how often furnaces and air conditioners run during a normal year.
On PlainClimate's composite comfort index, Crystal Lake scores 59/100 (Moderate), 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 Crystal Lake, IL? ▼
The average annual temperature in Crystal Lake, Illinois is 49°F. The warmest month averages 84°F (29°C) and the coldest averages 14°F (-10°C).
How much rain does Crystal Lake get? ▼
Crystal Lake receives 39.4 inches of precipitation annually, including 35.1 inches of snow. Based on NOAA 30-year climate normals (1991-2020).
What is the comfort score for Crystal Lake? ▼
Crystal Lake has a climate comfort score of 59/100 (Moderate), milder than 39% of U.S. cities in the PlainClimate database.
When is the growing season in Crystal Lake? ▼
Crystal Lake has approximately 180 frost-free days per year, with the last spring freeze around April 25 and the first fall freeze around October 22.
How much energy does heating and cooling require in Crystal Lake? ▼
Crystal Lake has 6,520 heating degree days and 771 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 Crystal Lake climate data come from? ▼
NOAA U.S. Climate Normals v1.0.1 (1991-2020), from weather station USC00112048 near Crystal Lake.
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). Station: USC00112048. 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.