Ontario sap flow forecast

The next several days for Ontario's sugaring country, read the way a sugarmaker reads them: how cold the night gets, how warm the afternoon gets, and whether that adds up to a run. The season here usually opens February (southwest) to March (north).

Lanark County, southwest of Ottawa, is billed as 'Ontario's Maple Syrup Capital' (Destination Ontario).

Forecast for Lanark

Updated Sep 26, 9:10 AM EDT

No freeze-thaw days in the forecast

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

  1. SunSep 27
    21°high
    11°low
    No freeze, no run

    Low of 52°F — trees need a hard freeze to reload. No freeze, no run.

  2. MonSep 28
    20°high
    12°low
    No freeze, no run

    Low of 54°F — trees need a hard freeze to reload. No freeze, no run.

  3. TueSep 29
    20°high
    9°low
    No freeze, no run

    Low of 48°F — trees need a hard freeze to reload. No freeze, no run.

  4. WedSep 30
    23°high
    10°low
    No freeze, no run

    Low of 50°F — trees need a hard freeze to reload. No freeze, no run.

  5. ThuOct 1
    19°high
    14°low
    No freeze, no run

    Low of 57°F — trees need a hard freeze to reload. No freeze, no run.

  6. FriOct 2
    19°high
    14°low
    No freeze, no run

    Low of 57°F — trees need a hard freeze to reload. No freeze, no run.

Data: Environment and Climate Change Canada. Verdicts use freeze-thaw thresholds from maple field research; your woods may run a little differently.

Southwestern Ontario reference point (Waterloo Region), the part of the province OMAFRA says taps earliest.

Forecast for Elmira

Updated Sep 26, 9:31 AM EDT

No freeze-thaw days in the forecast

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

  1. SunSep 27
    20°high
    8°low
    No freeze, no run

    Low of 46°F — trees need a hard freeze to reload. No freeze, no run.

  2. MonSep 28
    21°high
    11°low
    No freeze, no run

    Low of 52°F — trees need a hard freeze to reload. No freeze, no run.

  3. TueSep 29
    23°high
    9°low
    No freeze, no run

    Low of 48°F — trees need a hard freeze to reload. No freeze, no run.

  4. WedSep 30
    24°high
    12°low
    No freeze, no run

    Low of 54°F — trees need a hard freeze to reload. No freeze, no run.

  5. ThuOct 1
    20°high
    13°low
    No freeze, no run

    Low of 55°F — trees need a hard freeze to reload. No freeze, no run.

  6. FriOct 2
    19°high
    12°low
    No freeze, no run

    Low of 54°F — trees need a hard freeze to reload. No freeze, no run.

Data: Environment and Climate Change Canada. Verdicts use freeze-thaw thresholds from maple field research; your woods may run a little differently.

Northern Ontario sugarbush area named by Destination Ontario; OMAFRA says northern regions tap 2–3 weeks after the southwest.

Forecast for St. Joseph Island

Updated Sep 26, 5:30 AM EDT

No freeze-thaw days in the forecast

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

  1. SunSep 27
    22°high
    9°low
    No freeze, no run

    Low of 48°F — trees need a hard freeze to reload. No freeze, no run.

  2. MonSep 28
    21°high
    8°low
    No freeze, no run

    Low of 46°F — trees need a hard freeze to reload. No freeze, no run.

  3. TueSep 29
    21°high
    8°low
    No freeze, no run

    Low of 46°F — trees need a hard freeze to reload. No freeze, no run.

  4. WedSep 30
    19°high
    11°low
    No freeze, no run

    Low of 52°F — trees need a hard freeze to reload. No freeze, no run.

  5. ThuOct 1
    19°high
    11°low
    No freeze, no run

    Low of 52°F — trees need a hard freeze to reload. No freeze, no run.

  6. FriOct 2
    15°high
    9°low
    No freeze, no run

    Low of 48°F — trees need a hard freeze to reload. No freeze, no run.

Data: Environment and Climate Change Canada. Verdicts use freeze-thaw thresholds from maple field research; your woods may run a little differently.

Somewhere else in Ontario?

Your sugarbush, your forecast

Hourly temperatures for your exact spot, turned into a day-by-day sap-run outlook. US and Canada.

Planning ahead? Typical tapping dates for Ontario →

Data & method

  1. MSC GeoMet — city page weather — Environment and Climate Change Canada
  2. Sap flow in sugar maple: timing and weather drivers (Frontiers in Agronomy, 2025) — de Lima Santos et al.
  3. Maple Sugaring Tips for Beginners and Backyard Maple Sugar Producers — UNH Extension
  4. North American Maple Syrup Producers Manual, 2nd ed. (Bulletin 856) — The Ohio State University Extension

Never miss the first run

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