108 weather stations · 1951–2026
Is maple season moving earlier?
We scored 75 years of daily temperatures at 108 long-record weather stations across the maple belt with the same freeze-thaw rule our forecast and county atlas use. The season's closing signal now arrives earlier at 71 stations and later at none. The median shift is about -13 days since the 1950s.
- Season ends earlier
- 71 / 108
- stations, significant
- Season ends later
- 0
- stations, significant
- Median shift, closing
- -1.7 d
- per decade
- Median shift, opening
- -1.5 d
- per decade
What moved, and what didn't
Both ends of the season moved. The opening signal arrives earlier at 65 stations (median -1.5 days per decade) and the closing signal at 71 (median -1.7 days per decade); neither moved significantly later anywhere. Over 75 years that is roughly -11 and -13 days.
The number of sap days is a different story. Across all stations the median trend is 0 days per decade, but that hides a split: in the north (stations at or above 44°N) the median is +0.6 days per decade, in the south (below 40°N) -0.8. Warmer winters give the far north more days that cross freezing; at the warm edge they take freezing nights away.
This matches what maple researchers have reported from sugarbush records and climate models: the season is shifting earlier faster than it is shortening, and the warm edge of the range is where sugaring gets harder first. Our contribution is the station-by-station record, with the same rule applied everywhere, and every number reproducible from public data.
Ten familiar cities
| City | Opening, then | Opening, now | Closing, then | Closing, now | Sap days then → now |
|---|---|---|---|---|---|
| Burlington, VT | Mar 15 | Mar 3 | Apr 17 | Apr 5 | 33 → 32 |
| Albany, NY | Mar 6 | Feb 23 | Apr 8 | Mar 26 | 41.5 → 38.5 |
| Syracuse, NY | Mar 3 | Feb 21 | Apr 5 | Mar 25 | 33.5 → 34 |
| Concord, NH | Mar 10 | Mar 1 | Apr 12 | Apr 4 | 54 → 55 |
| Portland, ME | Mar 12 | Mar 3 | Apr 13 | Apr 6 | 48 → 46 |
| Madison, WI | Mar 12 | Feb 28 | Apr 12 | Mar 31 | 35.5 → 36.5 |
| Lansing, MI | Mar 9 | Feb 25 | Apr 6 | Mar 28 | 33 → 35 |
| Cleveland, OH | Feb 14 | Feb 11 | Mar 18 | Mar 14 | 33.5 → 30 |
| Pittsburgh, PA | Feb 7 | Feb 2 | Mar 10 | Mar 3 | 37 → 36.5 |
| Elkins, WV | Jan 27 | Jan 28 | Mar 2 | Mar 3 | 62 → 58.5 |
Every station
All 108 stations, sorted by how fast the closing moved
Days per decade; negative means earlier. Bold rows are significant at p < 0.05. 'Then' and 'now' are the medians of 1951–1980 and 1997–2026.
| Station | Seasons | Opening trend | Opening then → now | Closing trend | Closing then → now | Sap days trend |
|---|---|---|---|---|---|---|
| New Philadelphia, OH | 63 | -3.2 | Feb 15 → Jan 31 | -3.3 | Mar 18 → Mar 5 | -1.2 |
| Milwaukee, WI | 76 | -3 | Mar 12 → Feb 24 | -2.7 | Apr 10 → Mar 27 | 0 |
| Albany, NY | 76 | -2.3 | Mar 6 → Feb 23 | -2.6 | Apr 8 → Mar 26 | 0 |
| Fredonia, NY | 73 | -2.2 | Feb 24 → Feb 11 | -2.6 | Mar 26 → Mar 16 | -1 |
| Islip, NY | 63 | -2.6 | Feb 10 → Feb 1 | -2.6 | Mar 16 → Mar 4 | -0.2 |
| Oswego, NY | 67 | -2.1 | Mar 4 → Feb 26 | -2.6 | Apr 3 → Mar 25 | 0 |
| Burlington, IA | 74 | -1.9 | Feb 21 → Feb 8 | -2.5 | Mar 22 → Mar 9 | -0.5 |
| Peoria, IL | 76 | -2 | Feb 18 → Feb 9 | -2.5 | Mar 23 → Mar 9 | -0.2 |
| Burlington, VT | 76 | -2.4 | Mar 15 → Mar 3 | -2.5 | Apr 17 → Apr 5 | 0 |
| Madison, WI | 76 | -2.2 | Mar 12 → Feb 28 | -2.5 | Apr 12 → Mar 31 | 0 |
| Worcester, MA | 76 | -2.4 | Mar 6 → Feb 21 | -2.4 | Apr 5 → Mar 26 | -0.9 |
| Toledo, OH | 76 | -2.2 | Feb 24 → Feb 12 | -2.4 | Mar 28 → Mar 17 | -0.4 |
| La Crosse, WI | 75 | -2.6 | Mar 12 → Feb 26 | -2.4 | Apr 10 → Mar 28 | +1.2 |
| Des Moines, IA | 76 | -2.5 | Feb 26 → Feb 13 | -2.3 | Mar 28 → Mar 19 | +0.2 |
| Spencer, IA | 67 | -2.5 | Mar 12 → Feb 28 | -2.3 | Apr 13 → Apr 3 | +1.4 |
| Waterloo, IA | 75 | -2.3 | Mar 8 → Feb 23 | -2.3 | Apr 10 → Mar 26 | +1.3 |
| Rockford, IL | 76 | -2.3 | Mar 4 → Feb 21 | -2.3 | Apr 5 → Mar 24 | +0.8 |
| Milton, MA | 73 | -2.4 | Feb 27 → Feb 14 | -2.3 | Mar 31 → Mar 21 | +0.3 |
| Battle Creek, MI | 75 | -2 | Mar 4 → Feb 21 | -2.3 | Apr 3 → Mar 24 | 0 |
| Muskegon, MI | 76 | -2.6 | Mar 10 → Feb 24 | -2.3 | Apr 10 → Mar 29 | +0.9 |
| Binghamton, NY | 75 | -2.4 | Mar 12 → Feb 28 | -2.3 | Apr 12 → Mar 28 | +0.3 |
| Rochester, NY | 76 | -2.3 | Mar 4 → Feb 19 | -2.3 | Apr 3 → Mar 24 | 0 |
| Erie, PA | 76 | -2.3 | Feb 25 → Feb 13 | -2.3 | Mar 28 → Mar 17 | -0.3 |
| Philadelphia, PA | 76 | -1.4 | Jan 30 → Jan 21 | -2.3 | Mar 3 → Feb 16 | -1.2 |
| Dubuque, IA | 76 | -2.2 | Mar 10 → Feb 26 | -2.2 | Apr 10 → Mar 29 | +0.7 |
| Moline, IL | 76 | -2.4 | Feb 27 → Feb 14 | -2.2 | Mar 29 → Mar 19 | +1 |
| Lansing, MI | 73 | -2.3 | Mar 9 → Feb 25 | -2.2 | Apr 6 → Mar 28 | +0.5 |
| Poughkeepsie, NY | 72 | -2 | Feb 25 → Feb 14 | -2.2 | Mar 30 → Mar 19 | +0.2 |
| Avoca, PA | 76 | -2.3 | Feb 24 → Feb 13 | -2.2 | Mar 27 → Mar 17 | +0.9 |
| Bridgeport, CT | 76 | -2 | Feb 15 → Feb 4 | -2.1 | Mar 18 → Mar 7 | -0.5 |
| Detroit, MI | 76 | -2.4 | Mar 1 → Feb 17 | -2.1 | Mar 29 → Mar 19 | +0.6 |
| Columbus, OH | 76 | -1.6 | Feb 7 → Jan 28 | -2.1 | Mar 10 → Feb 27 | -1.2 |
| Mount Pocono, PA | 60 | -1.9 | Mar 6 → Feb 23 | -2.1 | Apr 8 → Mar 29 | -1.1 |
| Boston, MA | 76 | -1.7 | Feb 17 → Feb 7 | -2 | Mar 17 → Mar 5 | 0 |
| Flint, MI | 76 | -2.4 | Mar 10 → Feb 25 | -2 | Apr 6 → Mar 30 | +1.3 |
| Grand Rapids, MI | 76 | -2 | Mar 8 → Feb 24 | -2 | Apr 6 → Mar 27 | 0 |
| Saginaw, MI | 76 | -2.3 | Mar 14 → Feb 28 | -2 | Apr 10 → Mar 30 | +1.4 |
| Buffalo, NY | 76 | -1.7 | Mar 3 → Feb 24 | -2 | Apr 2 → Mar 25 | -0.4 |
| Syracuse, NY | 76 | -1.9 | Mar 3 → Feb 21 | -2 | Apr 5 → Mar 25 | +0.3 |
| Youngstown, OH | 76 | -1.7 | Feb 24 → Feb 12 | -2 | Mar 24 → Mar 15 | 0 |
| Allentown, PA | 76 | -2.2 | Feb 18 → Feb 7 | -2 | Mar 22 → Mar 13 | +0.6 |
| Hartford, CT | 75 | -1.7 | Feb 23 → Feb 16 | -1.9 | Mar 29 → Mar 21 | +0.5 |
| Fort Wayne, IN | 76 | -1.8 | Feb 22 → Feb 13 | -1.9 | Mar 25 → Mar 15 | 0 |
| Mansfield, OH | 76 | -1.6 | Feb 19 → Feb 11 | -1.9 | Mar 23 → Mar 14 | -0.2 |
| Eau Claire, WI | 76 | -2.1 | Mar 15 → Mar 6 | -1.9 | Apr 16 → Apr 7 | +1.1 |
| Holland, MI | 67 | -1.2 | Mar 4 → Feb 23 | -1.8 | Apr 1 → Mar 23 | -0.7 |
| Minneapolis-St Paul, MN | 76 | -2.5 | Mar 16 → Mar 4 | -1.8 | Apr 12 → Apr 4 | +0.6 |
| Rochester, MN | 76 | -1.7 | Mar 17 → Mar 11 | -1.8 | Apr 14 → Apr 6 | 0 |
| Akron, OH | 76 | -1.1 | Feb 16 → Feb 11 | -1.8 | Mar 23 → Mar 14 | -0.7 |
| Green Bay, WI | 76 | -2.2 | Mar 18 → Mar 8 | -1.8 | Apr 16 → Apr 6 | +0.6 |
| Quincy, IL | 76 | -1.3 | Feb 10 → Feb 2 | -1.7 | Mar 12 → Mar 5 | -0.2 |
| Indianapolis, IN | 76 | -0.8 | Feb 8 → Feb 2 | -1.7 | Mar 10 → Feb 28 | -1.3 |
| Portland, ME | 76 | -1.8 | Mar 12 → Mar 3 | -1.7 | Apr 13 → Apr 6 | -0.7 |
| New York-Kennedy Airport, NY | 76 | -1.5 | Feb 2 → Jan 23 | -1.7 | Mar 5 → Feb 22 | +0.2 |
| Zanesville, OH | 76 | -1.6 | Feb 4 → Jan 27 | -1.7 | Mar 9 → Feb 28 | -1.4 |
| Williamsport, PA | 76 | -2 | Feb 22 → Feb 11 | -1.7 | Mar 25 → Mar 15 | 0 |
| Martinsburg, WV | 76 | -1.4 | Jan 28 → Jan 24 | -1.7 | Mar 3 → Feb 22 | -0.6 |
| Wheeling, WV | 67 | -0.5 | Feb 1 → Jan 30 | -1.6 | Mar 6 → Feb 23 | -3.8 |
| Cedar Rapids, IA | 76 | -1.4 | Mar 2 → Feb 23 | -1.5 | Apr 1 → Mar 26 | +1 |
| Sioux City, IA | 76 | -2 | Feb 27 → Feb 19 | -1.5 | Mar 30 → Mar 24 | +2.1 |
| Chicago, IL | 76 | -1.5 | Feb 26 → Feb 17 | -1.5 | Mar 28 → Mar 15 | +0.5 |
| South Bend, IN | 76 | -1.3 | Feb 23 → Feb 17 | -1.5 | Mar 27 → Mar 18 | +0.6 |
| Millinocket, ME | 74 | -1.1 | Mar 23 → Mar 17 | -1.5 | Apr 24 → Apr 18 | -0.2 |
| Kalamazoo, MI | 62 | -1.1 | Feb 24 → Feb 19 | -1.5 | Mar 30 → Mar 24 | -0.7 |
| St Louis, MO | 76 | -1.1 | Jan 25 → Jan 19 | -1.5 | Feb 28 → Feb 16 | -1.1 |
| Concord, NH | 76 | -1.6 | Mar 10 → Mar 1 | -1.5 | Apr 12 → Apr 4 | 0 |
| Pittsburgh, PA | 76 | -0.9 | Feb 7 → Feb 2 | -1.5 | Mar 10 → Mar 3 | -0.2 |
| Cleveland, OH | 76 | -0.9 | Feb 14 → Feb 11 | -1.4 | Mar 18 → Mar 14 | -0.7 |
| Dayton, OH | 76 | -0.8 | Feb 7 → Feb 3 | -1.4 | Mar 9 → Mar 2 | -0.2 |
| Alpena, MI | 72 | -1.3 | Mar 19 → Mar 14 | -1.3 | Apr 20 → Apr 16 | 0 |
| Wausau, WI | 76 | -1.7 | Mar 18 → Mar 10 | -1.3 | Apr 17 → Apr 11 | +0.5 |
| Springfield, IL | 75 | -1.3 | Feb 9 → Jan 30 | -1.2 | Mar 11 → Mar 6 | +0.3 |
| Duluth, MN | 76 | -1.4 | Mar 29 → Mar 21 | -1.2 | Apr 27 → Apr 23 | +0.3 |
| Middletown-Harrisburg, PA | 76 | -1 | Feb 7 → Feb 1 | -1.2 | Mar 11 → Mar 6 | +0.8 |
| Caribou, ME | 76 | -0.8 | Mar 30 → Mar 27 | -1.1 | Apr 30 → Apr 25 | +0.6 |
| Saint Cloud, MN | 76 | -1.3 | Mar 19 → Mar 12 | -1.1 | Apr 18 → Apr 11 | +0.7 |
| Glens Falls, NY | 76 | -1.1 | Mar 11 → Mar 6 | -1.1 | Apr 13 → Apr 8 | +1.8 |
| Cincinnati, OH | 76 | -0.6 | Jan 27 → Jan 22 | -1.1 | Mar 2 → Feb 18 | -0.9 |
| Wilmington, OH | 75 | -0.7 | Feb 2 → Jan 29 | -1.1 | Mar 6 → Mar 1 | -1.9 |
| Bluefield, WV | 75 | -0.3 | Jan 19 → Jan 16 | -1.1 | Feb 18 → Feb 11 | -1.5 |
| Paducah, KY | 76 | 0 | Jan 13 → Jan 11 | -1 | Feb 11 → Feb 7 | -0.4 |
| New York-Central Park, NY | 76 | -0.7 | Jan 28 → Jan 24 | -0.9 | Mar 1 → Feb 20 | -1 |
| Lexington, KY | 76 | 0 | Jan 20 → Jan 16 | -0.8 | Feb 15 → Feb 12 | -0.8 |
| Sault Ste Marie, MI | 76 | -1 | Mar 28 → Mar 24 | -0.8 | Apr 27 → Apr 22 | -0.5 |
| Columbia, MO | 76 | -0.7 | Jan 28 → Jan 23 | -0.8 | Feb 26 → Feb 21 | -0.6 |
| Plattsburgh, NY | 66 | -0.9 | Mar 11 → Mar 8 | -0.8 | Apr 13 → Apr 11 | +0.3 |
| Ashland, WI | 70 | -1.3 | Mar 24 → Mar 17 | -0.8 | Apr 24 → Apr 21 | +0.4 |
| Clarksburg, WV | 65 | -0.2 | Jan 26 → Jan 22 | -0.8 | Feb 27 → Feb 22 | -2.9 |
| Morgantown, WV | 73 | 0 | Jan 25 → Jan 22 | -0.8 | Feb 27 → Feb 21 | -0.6 |
| Bangor, ME | 71 | -1.2 | Mar 17 → Mar 12 | -0.7 | Apr 17 → Apr 16 | +1.5 |
| Houghton Lake, MI | 75 | -0.8 | Mar 17 → Mar 13 | -0.7 | Apr 20 → Apr 15 | +0.6 |
| Huntington, WV | 76 | +0.3 | Jan 14 → Jan 16 | -0.7 | Feb 14 → Feb 11 | -1.6 |
| Evansville, IN | 76 | -0.2 | Jan 20 → Jan 18 | -0.6 | Feb 21 → Feb 16 | -0.3 |
| Louisville, KY | 76 | 0 | Jan 15 → Jan 14 | -0.6 | Feb 13 → Feb 9 | -1.4 |
| New York-LGA, NY | 76 | -0.3 | Jan 29 → Jan 26 | -0.5 | Feb 24 → Feb 21 | -0.9 |
| Springfield, MO | 76 | -0.3 | Jan 15 → Jan 12 | -0.4 | Feb 15 → Feb 10 | -0.7 |
| Beckley, WV | 75 | 0 | Jan 21 → Jan 21 | -0.4 | Feb 25 → Feb 17 | -2.5 |
| Elkins, WV | 76 | -0.3 | Jan 27 → Jan 28 | -0.4 | Mar 2 → Mar 3 | -0.8 |
| Marquette County, MI | 65 | -0.4 | Mar 28 → Mar 25 | -0.3 | Apr 29 → Apr 27 | 0 |
| International Falls, MN | 75 | -0.8 | Mar 29 → Mar 25 | -0.3 | Apr 28 → Apr 27 | +1.6 |
| Reading, PA | 74 | -0.5 | Feb 1 → Jan 30 | -0.2 | Mar 5 → Mar 4 | +1.1 |
| Kansas City, MO | 76 | 0 | Jan 25 → Jan 24 | 0 | Feb 26 → Feb 26 | +1.1 |
| Rhinelander, WI | 67 | -0.3 | Mar 19 → Mar 19 | 0 | Apr 20 → Apr 16 | +0.8 |
| Parkersburg, WV | 71 | 0 | Jan 21 → Jan 22 | +0.3 | Feb 22 → Feb 21 | +0.4 |
| Charleston, WV | 76 | +0.2 | Jan 12 → Jan 13 | +0.6 | Feb 8 → Feb 10 | -0.2 |
| Carbondale, IL | 66 | +0.6 | Jan 13 → Jan 19 | +0.7 | Feb 15 → Feb 16 | -1.4 |
| Hibbing, MN | 74 | 0 | Mar 27 → Mar 23 | +0.7 | Apr 25 → Apr 24 | +2.6 |
| Philadelphia Center City, PA | 72 | +0.8 | Jan 21 → Jan 26 | +0.7 | Feb 16 → Feb 19 | -0.6 |
FAQ
Questions about the trend
- Is maple sugaring season getting earlier?
- By this record, yes. At 71 of 108 long-record stations the weather signal that ends the season now arrives significantly earlier than it did in the 1950s and 60s, and at none does it arrive later; the median shift is about -13 days over 75 years. The opening signal shows the same pattern (65 stations earlier, none later).
- Are there fewer sap days?
- Not everywhere. The count of freeze-thaw sap days fell significantly at 23 stations, mostly in the southern half of the belt (West Virginia, Ohio, Kentucky, the Philadelphia area), and rose at 13, mostly in the north (Upper Michigan, northern Minnesota, Maine, Iowa), where warmer winters mean more days that cross freezing. The season is shifting more than it is shrinking.
- What do 'opening' and 'closing' signals mean here?
- They are weather signals, not what producers did: the closing signal is the last freeze-thaw sap day before accumulated warmth since Jan 1 reaches a fixed threshold, and the opening signal sits five weeks before that date, never earlier than the first real freeze-thaw week. The same rule, tested against USDA's reported season dates (within about 5–7 days on average), drives the county atlas.
- How reliable are 75-year station records?
- ThreadEx records stitch each city's current airport station to its predecessors, so site moves and growing cities can leave a mark in temperatures. We only use seasons with at least 95% of days observed, keep only stations with 60 or more complete seasons, and test each trend with the Mann–Kendall test (p < 0.05 counts as significant). The direction is consistent across almost every station, which is harder to explain by site moves than a few outliers would be.
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