Your nature year
Decatur, Illinoisthrough the year
When do frost, green-up and fall color come to Decatur?
The USA-NPN spring index puts first leaf here around Mar 25 and first bloom around Apr 23. Spring takes about 4 weeks to go from leaf to bloom.
Expect about 193 frost-free days in Decatur: the last spring frost usually comes around Apr 14, the first fall one around Oct 24, going by NOAA's Decatur Wtp station 2.1 miles away. Chautauqua Refuge, 66 miles from Decatur, is the nearest winter wildlife spot on this site, Migration typically peaks in November (usually). For spring migration, the nearest is Port Louisa Refuge (149 mi, April to May (local timing)). Head northwest for the closest of the 5 places we follow around Decatur. Statewide, Illinois' fall color is usually well under way by late October.
Updated Sep 29. Sources: US Census Bureau, 2024 Gazetteer (places) ↗ (opens in a new tab), US Census Bureau, city and town population estimates, 2024 ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) ↗ (opens in a new tab)
Near Decatur right now
- Fall color is usually well under way by late October in IllinoisStatewide · USA-NPN volunteer observations, 2020–2025 · not a forecast~4 weeks
- First fall frost usually around Oct 24 · last spring frost around Apr 14NOAA 1991–2020 normals, Decatur Wtp (2.1 mi, 50% dates)~3 weeks
- Winter wildlife · Chautauqua Refuge · 66 miUsually: Migration typically peaks in November~5 weeks
Your guide around Decatur
Nearby, season by season
Spring migration
- Port Louisa Refuge · 149 miLocal timing: April to May~6 months
Winter wildlife
- Chautauqua Refuge · 66 miUsually: Migration typically peaks in November~5 weeks
- Emiquon Refuge · 69 miUsually: migration typically peaks in November~5 weeks
- Meredosia Refuge · 86 miUsually: migration typically peaks in November~5 weeks
Decatur's nature year
- Mar: Spring green-upMar
- Spring migration · Port Louisa RefugeApr–May
- Apr: Last spring frostApr
- Oct: Fall color (IL)Oct
- Oct: First fall frostOct
- Nov: Winter wildlife · Chautauqua RefugeNov
Decatur's year at a glance
- Frost possible
- Frost-free, ~Apr 14 to ~Oct 24
- First leaf ~Mar 25
- First bloom ~Apr 23
- Fall color under way ~Oct 27 (IL)
- Today
Frost and green-up
Last spring frost
Apr 14
Average (50% date)
First fall frost
Oct 24
About 193 days without frost between
Spring green-up
Mar 25
First bloom around Apr 23
Frost: NOAA 1991–2020 climate normals at Decatur Wtp (2.1 mi from Decatur), the day a 32 °F night is as likely as not. Green-up: the USA-NPN Spring Index, 1991–2020 average at the town.
Snow in Decatur
Snow usually becomes possible around Jan 8 (our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%). NOAA's normals at Decatur Wtp (2.1 mi away): 14 inches of snow in an average year, about 5.6 days with 1 inch or more.
NOAA's chance of at least 0.1 inch of snow on each date (one value per week, September to May), averaged over 1991–2020. A typical year, not a forecast.
Questions people ask
When is the first frost in Decatur?
On average around Oct 24, and the last spring frost around Apr 14: about 193 days without frost between. These are NOAA's 1991–2020 normals at Decatur Wtp, 2.1 miles away (the day a 32 °F night is as likely as not).
When does spring green-up reach Decatur?
The USA-NPN Spring Index puts first leaf around Mar 25 and first bloom around Apr 23, on average for 1991–2020 at the town.
Where can I see spring migration near Decatur?
Port Louisa Refuge, 149 miles (local timing: April to May). Distances are straight-line.
Where can I see winter wildlife near Decatur?
Chautauqua Refuge, 66 miles (usually: Migration typically peaks in November); Emiquon Refuge, 69 miles (usually: migration typically peaks in November); Meredosia Refuge, 86 miles (usually: migration typically peaks in November). Distances are straight-line.
When does it start snowing in Decatur?
Snow usually becomes possible around Jan 8: our calculation from NOAA's daily snow chances: the first day the chance of 0.1" or more of snow reaches 10%, at Decatur Wtp. An average year brings 14 inches (NOAA 1991–2020). A typical year, not a forecast.Sources: NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal snowfall) ↗ (opens in a new tab), NOAA NCEI U.S. Climate Normals 1991–2020 (daily snowfall probabilities) ↗ (opens in a new tab)
How we know
US Census Bureau, 2024 Gazetteer (places) (opens in a new tab) (Sep 27) · US Census Bureau, city and town population estimates, 2024 (opens in a new tab) (Sep 27) · NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal) (opens in a new tab) (Sep 27) · USA National Phenology Network, Spring Index 1991–2020 averages (opens in a new tab) (Sep 27) · USA National Phenology Network, colored leaves observations (opens in a new tab) (Sep 29)