When to tap maple trees in Kentucky

Maple season in Kentucky usually opens late December to early January and winds down late February. Here's the long-run pattern, the year-by-year record, and what the forecast says right now.

Typical season
Opens
late December to early January
Closes
late February
Sap-flow outlook right now

Forecast for Marion

Updated Sep 26, 9:16 AM EDT

No freeze-thaw days in the forecast

Blue = below 32°F · Amber = thaw · dashed line = freezing

  1. SunSep 27
    72°high
    55°low
    0h frozen
    24h thawed
    No freeze, no run
  2. MonSep 28
    73°high
    50°low
    0h frozen
    24h thawed
    No freeze, no run
  3. TueSep 29
    78°high
    53°low
    0h frozen
    24h thawed
    No freeze, no run
  4. WedSep 30
    80°high
    62°low
    0h frozen
    24h thawed
    No freeze, no run
  5. ThuOct 1
    78°high
    69°low
    0h frozen
    24h thawed
    No freeze, no run
  6. FriOct 2
    78°high
    65°low
    0h frozen
    20h thawed
    No freeze, no run

Data: National Weather Service. Verdicts use freeze-thaw thresholds from maple field research; your woods may run a little differently.

Full Kentucky sap forecast →
How to know it's time

Sap runs on a temperature swing, not a date. A night below freezing loads the tree; a day above freezing pushes sap out of the taphole. Field research treats a low under about 30°F followed by a high over about 37°F as a real freeze-thaw day, and big runs almost always come on days like that.

So watch the 10-day forecast. When you see a string of nights in the 20s and afternoons in the 40s, get your taps in a day or two ahead. Tap south-facing slopes first — they warm and run earlier.

No NASS season data for Kentucky. Current guidance from the Kentucky Maple Syrup Association, the University of Kentucky and the Kentucky Department of Agriculture is to tap in late December or early January; the association says the season typically ends in late February, depending on weather. An older UK Extension bulletin (FOR-118, 2010) instead advised northern Kentucky to tap between Valentine's Day and St. Patrick's Day, earlier farther south.

Seasons are shifting. In New England and New York, the sugaring season now begins about 8 days earlier and ends about 11 days earlier than it did 40 years earlier, leaving it roughly 3 days (about 10%) shorter, according to UVM Proctor Maple Research Center survey records analyzed in 2007.

Common questions

When is maple syrup season in Kentucky?
Usually from late December to early January to late February. The exact start moves by weeks from year to year with the weather.
When should I tap my trees in Kentucky?
Tap just before the first good run: when the forecast shows nights below freezing and days climbing to around 40°F. Tapholes dry up within 6 to 10 weeks, so tapping far too early can cost you the late runs.
What weather makes sap run?
Freezing nights and thawing days. Field research counts a freeze-thaw day as a low under about 30°F and a high over about 37°F; nights in the 20s and days in the 40s are the classic sap days.
Other states

Get a heads-up when Kentucky's sap will run

LuckySap checks the forecast for your trees and can ping you the night before a strong sap day — then keeps every collection and boil in one season log. Free on iPhone.

Download on the App Store