Best Time to See Great Blue Herons in Illinois
May, August and July is the best time to see great blue herons in Illinois. Based on 8,611 verified iNaturalist observations, here is exactly when great blue herons are most active across the year in Illinois.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated July 20, 2026.
Great Blue Heron · Becca CC BY
Great Blue Heron · Peter Chen 2.0 CC BY
Great Blue Heron · Dmitry Mozzherin CC BY
8,611 verified observations of great blue herons in Illinois, recorded across 12 months of the year on iNaturalist.
When great blue herons are recorded in Illinois
Peak month
May
1,277 records (14.8% of the year)
| Month | Observations | Share |
|---|---|---|
| January | 155 | 1.8% |
| February | 144 | 1.7% |
| March | 390 | 4.5% |
| April | 1,075 | 12.5% |
| Maypeak | 1,277 | 14.8% |
| June | 947 | 11% |
| Julypeak | 1,151 | 13.4% |
| Augustpeak | 1,161 | 13.5% |
| September | 1,109 | 12.9% |
| October | 706 | 8.2% |
| November | 298 | 3.5% |
| December | 198 | 2.3% |
Great Blue Herons you are most likely to see
| Species | Verified observations |
|---|---|
| Great Blue Heron | 8,611 |
Weather to expect, source Open-Meteo
Typical weather in Illinois
Recent typical conditions by month, so you can plan a trip around both when great blue herons are active and what the weather is doing. The best months to look for great blue herons sit around 54 to 85 degrees Fahrenheit, so pack for that.
| Month | Avg high | Avg low | Rain |
|---|---|---|---|
| Jan | 38°F | 23°F | 3" |
| Feb | 40°F | 22°F | 3.1" |
| Mar | 53°F | 34°F | 4.8" |
| Apr | 63°F | 43°F | 4.1" |
| Maybest time | 73°F | 54°F | 4.6" |
| Jun | 83°F | 64°F | 3.5" |
| Julbest time | 85°F | 68°F | 4.3" |
| Augbest time | 83°F | 66°F | 3.9" |
| Sep | 79°F | 61°F | 3" |
| Oct | 65°F | 48°F | 4.9" |
| Nov | 52°F | 35°F | 1.8" |
| Dec | 45°F | 29°F | 2.3" |
Typical recent conditions (5-year means) from the Open-Meteo archive, averaged for Illinois. Weather varies year to year, so treat these as a guide.
Sightings of great blue herons in Illinois peak in May, when 1,277 of the year's 8,611 verified observations are logged — about 14.8% of the annual total. Activity stays high through May, August and July.
The quietest stretch is February, January and December, when great blue herons are hardest to find — February sees just 144 records. If a reliable sighting matters, plan around the peak window rather than the off-season.
The great blue herons you are most likely to encounter in Illinois are Great Blue Heron — the most-recorded species in the state. Each keeps its own seasonal rhythm, but the month-by-month pattern above reflects every reported sighting together.
Where to go
Best places to see great blue herons in Illinois
- Lewis & Clark National Historic Trail — National Historic Trail
- Lincoln Home National Historic Site — National Historic Site
- Emmett Till and Mamie Till-Mobley National Monument — National Monument
- Mormon Pioneer National Historic Trail — National Historic Trail
- New Philadelphia National Historic Site — National Historic Site
- Pullman National Historical Park — National Historical Park
Frequently asked questions
What is the best month to see great blue herons in Illinois?+
May is the single best month, and the broader peak window runs through May, August and July, based on 8,611 verified iNaturalist observations.
When are great blue herons hardest to see in Illinois?+
February is the quietest month for great blue herons in Illinois, with only 144 verified records.
Are great blue herons active year-round in Illinois?+
Great blue herons are recorded in 12 of 12 months in Illinois, so they can be seen year-round, with a clear peak in May.
More wildlife in Illinois