Growing degree days · base 50°F
Growing degree days in Naperville, IL
Season to date · since January 1
3,322GDD
Peak accumulated heat
The season has banked substantial heat. Warm-season grass is at its strongest; cool-season grass may be under heat stress and should not be pushed with nitrogen.
This week in Naperville
Naperville, IL added 96 growing degree days this past week, 13.7 a day, reaching 3,322 for the season. Its warmest day added 21.
| Day | Added | Season total |
|---|---|---|
| Tue | 10 | 3,235 |
| Wed | 16 | 3,251 |
| Thu | 9 | 3,260 |
| Fri | 9 | 3,270 |
| Sat | 18 | 3,288 |
| Sun | 13 | 3,301 |
| Mon | 21 | 3,322 |
PGR reapplication tracking
Plant growth regulator timing uses a Celsius-scale accumulation, not the seasonal Fahrenheit one. This page tracks a 10°C base, which is the Bermuda (warm-season) figure. Trinexapac-ethyl is typically re-sprayed near 200 GDD on cool-season turf and roughly 216 to 230 on warm-season turf, measured from your last application rather than from January. Always follow the product label.
Track GDD from your own spray date →Soil temperature right now in Naperville, IL
GDD is a trend indicator. Soil temperature is the signal that actually decides pre-emergent and seeding timing, and it is 61.7°F here at 2 inches.
Full soil report for 60540 →Nearby
Growing degree days near Naperville
Get this number every morning
This page recalculates when you load it. The app accumulates GDD for Naperville, IL daily and tells you when your PGR window opens. Free on iPhone and Android.