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Ontario · maple atlas

Maple sugaring in Stormont, Dundas and Glengarry, Ontario

Stormont, Dundas and Glengarry is one of Ontario's united counties. Ontario's census divisions are its counties, districts and regional municipalities. Statistics Canada's 2021 Census of Agriculture counted 87 farms reporting maple taps and 57,897 taps here. Around Cornwall, sap usually runs from March 12 to April 12. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 156 days until the usual start.
Sap starts
Mar 12
weather estimate
Season ends
Apr 12
about 4 weeks
Sap days / season
29.6
1991–2025 average
Taps, 2021
57,897
#10 of 29 in ON

Sap-flow outlook at Cornwall right now

Full Ontario forecast →

Forecast for Cornwall, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Stormont, Dundas and Glengarry's season usually opens around March 12, which is 156 days away.

No freeze-thaw days in the forecast

freeze thaw 0 °C

  1. ThuOct 8
    8° / 17°
    No refreeze forecast
  2. FriOct 9
    8° / 14°
    No refreeze forecast
  3. SatOct 10
    1° / 15°
    No refreeze forecast
  4. SunOct 11
    10° / 23°
    No refreeze forecast
  5. MonOct 12
    12° / 19°
    No refreeze forecast
  6. TueOct 13
    10° / 14°
    No refreeze forecast

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

When the sap runs

The sugaring calendar at Cornwall

Freeze-thaw weather at Cornwall peaks in the weeks of Mar 9 to Apr 6, which hold about 42% of a season's sap days. March is the busiest month. Typical dates are a weather estimate (no official season record for this province): the median of this division's own weather signals.
Typical season: Mar 12 – Apr 120246Week of Dec 1: 1.1 sap days on averageWeek of Dec 8: 1.4 sap days on averageWeek of Dec 15: 0.9 sap days on averageWeek of Dec 22: 0.8 sap days on averageWeek of Dec 29: 0.9 sap days on averageWeek of Jan 5: 0.8 sap days on averageWeek of Jan 12: 0.7 sap days on averageWeek of Jan 19: 0.7 sap days on averageWeek of Jan 26: 0.5 sap days on averageWeek of Feb 2: 0.8 sap days on averageWeek of Feb 9: 0.9 sap days on averageWeek of Feb 16: 1.1 sap days on averageWeek of Feb 23: 1.4 sap days on averageWeek of Mar 2: 1.5 sap days on averageWeek of Mar 9: 2.1 sap days on averageWeek of Mar 16: 2.3 sap days on averageWeek of Mar 23: 2.7 sap days on averageWeek of Mar 30: 3.0 sap days on averageWeek of Apr 6: 2.5 sap days on averageWeek of Apr 13: 1.6 sap days on averageWeek of Apr 20: 1.1 sap days on averageWeek of Apr 27: 0.7 sap days on averageWeek of May 4: 0.2 sap days on averageWeek of May 11: 0.1 sap days on averageWeek of May 18: 0.0 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 12
Average number of freeze-thaw sap days in each week of the season at Cornwall, 1991–2025 (Daymet temperatures). A sap day is an overnight low under −1 °C (30.2 °F) followed by an afternoon high over +3 °C (37.4 °F). The shaded band is the typical season.

Year-to-year spread

Opening signal
Median Mar 12; the middle half of seasons fell between Mar 7 and Mar 17. Earliest Feb 16 (2012), latest Apr 9 (2003).
Closing signal
Median Apr 12; middle half between Apr 7 and Apr 17. Earliest Mar 12 (2012), latest Apr 23 (2018).
Sap days by month
Dec15%Jan11%Feb14%Mar33%Apr26%May1%

35 seasons of sap weather

Stormont, Dundas and Glengarry seasons, 1991–2025

The best sap year at Cornwall was 2020 with 41 freeze-thaw days; the leanest was 2003 with 18. Seasons that start early tend to end early too: the trees run on the swing between freezing nights and mild days, and heat ends it.
JanFebMarAprMaysap days20252025: Mar 11 – Apr 14, 32 sap days3220242024: Feb 25 – Mar 31, 35 sap days3520232023: Mar 11 – Apr 9, 39 sap days3920222022: Mar 8 – Apr 11, 33 sap days3320212021: Mar 3 – Apr 6, 24 sap days2420202020: Mar 3 – Apr 7, 41 sap days4120192019: Mar 18 – Apr 17, 38 sap days3820182018: Mar 21 – Apr 23, 39 sap days3920172017: Mar 19 – Apr 3, 24 sap days2420162016: Mar 12 – Apr 16, 38 sap days3820152015: Mar 17 – Apr 19, 20 sap days2020142014: Mar 18 – Apr 20, 20 sap days2020132013: Mar 14 – Apr 15, 37 sap days3720122012: Feb 16 – Mar 12, 35 sap days3520112011: Mar 9 – Apr 8, 24 sap days2420102010: Feb 28 – Mar 28, 21 sap days2120092009: Mar 12 – Apr 14, 29 sap days2920082008: Mar 15 – Apr 16, 22 sap days2220072007: Mar 10 – Apr 11, 25 sap days2520062006: Mar 6 – Apr 9, 29 sap days2920052005: Mar 13 – Apr 16, 30 sap days3020042004: Mar 16 – Apr 17, 31 sap days3120032003: Apr 9 – Apr 18, 18 sap days1820022002: Mar 9 – Apr 7, 34 sap days3420012001: Mar 19 – Apr 19, 26 sap days2620002000: Feb 23 – Mar 28, 29 sap days2919991999: Mar 10 – Apr 12, 37 sap days3719981998: Mar 3 – Mar 25, 20 sap days2019971997: Mar 28 – Apr 15, 24 sap days2419961996: Mar 16 – Apr 16, 31 sap days3119951995: Mar 9 – Apr 11, 38 sap days3819941994: Mar 15 – Apr 18, 31 sap days3119931993: Mar 17 – Apr 7, 24 sap days2419921992: Mar 26 – Apr 17, 25 sap days2519911991: Mar 3 – Apr 3, 34 sap days34
Each bar runs from the season's opening signal to its closing signal, estimated from daily Daymet temperatures at Cornwall. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Stormont, Dundas and Glengarry in the Census of Agriculture

Statistics Canada counts the farms that report maple taps in its Census of Agriculture every five years. In 2021 it counted 87 in Stormont, Dundas and Glengarry, with 57,897 taps; in 2016, 104 farms and 42,884 taps. Among Ontario's 29 census divisions with a published tap count, Stormont, Dundas and Glengarry ranks 10th, and 69th of the 94 in this atlas.

Over the five years the farm count changed −16% and taps +35%. Statistics Canada cautions that 2021 and 2016 are not strictly comparable: the census-farm definition changed in 2021, and farms were assigned to their main location more strictly.

Statistics Canada doesn't publish syrup volume by census division, so the Canadian pages show farms and taps, not gallons or litres.

Stormont, Dundas and Glengarry maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
20218757,897E
201610442,884
  • E Statistics Canada quality grade: use with caution.

Nearby

Neighboring maple divisions

Distances are between reference towns; typical dates are each division's own estimate.

About these numbers

The season dates are estimated from 35 seasons of daily high and low temperatures for the Daymet 1-km grid cell at Cornwall, the division's most populous municipality in the 2021 Census; the cell sits at 53 m (174 ft). Each day is scored with the same freeze-thaw rule as our live forecast: a sap day is an overnight low under −1 °C (30.2 °F) followed by an afternoon high over +3 °C (37.4 °F). A season's closing signal is the last sap day before accumulated warmth reaches a threshold, and the opening signal sits 35 days before that, never earlier than the first real freeze-thaw week. The rule was calibrated on 117 state-seasons of USDA-reported dates in the US and is applied here unchanged. Ontario has no official season record, so the typical dates are a weather estimate. Production figures are copied from Statistics Canada as published. Full method, the Daymet checks and the Quebec validation → Run a sugarhouse here? Put this sap forecast on your own website →

Sources · 7

  1. 1.Maple taps, Census of Agriculture, 2021 (Table 32-10-0362-01) · Statistics Canada
  2. 2.Maple taps, Census of Agriculture, 2011 and 2016 (Table 32-10-0423-01) · Statistics Canada
  3. 3.Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 4 R1 · ORNL DAAC
  4. 4.Sap flow in sugar maple: timing and weather drivers (Frontiers in Agronomy, 2025) · de Lima Santos et al.
  5. 5.2021 Census cartographic boundary files (census divisions, population centres) · Statistics Canada
  6. 6.Population and dwelling counts, 2021 Census (Tables 98-10-0002-01 and 98-10-0011-01) · Statistics Canada
Show 1 more
  1. 7.GeoNames geographical database (CA) · GeoNames

Licences and attribution

  • Adapted from Statistics Canada, Census of Agriculture 2021 and 2016 (Tables 32-10-0362-01 and 32-10-0423-01), 2021 Census population and dwelling counts (Tables 98-10-0002-01 and 98-10-0011-01) and 2021 Census cartographic boundary files. This does not constitute an endorsement by Statistics Canada of this product.
  • Contains information licensed under the Open Government Licence – Canada.
  • Thornton, M.M., R. Shrestha, Y. Wei, P.E. Thornton, S-C. Kao, and B.E. Wilson. 2022. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 4 R1. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/2129
  • Place coordinates: GeoNames (geonames.org), CC BY 4.0.

FAQ

Stormont, Dundas and Glengarry sugaring questions

When should I tap maple trees in Stormont, Dundas and Glengarry, Ontario?
In a typical year the sap starts running around March 12 near Cornwall and the season winds down around April 12. Have your taps in a day or two before the first forecast string of nights below −1 °C and days above +3 °C. In the past 35 seasons the weather signal came as early as Feb 16 and as late as Apr 9.
How much maple syrup does Stormont, Dundas and Glengarry produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 87 farms reporting 57,897 maple taps in Stormont, Dundas and Glengarry, number 10 of 29 Ontario divisions with a published count.
How many sap days does Stormont, Dundas and Glengarry get in a season?
On average 29.6 freeze-thaw sap days from December through May at Cornwall, of which about 10.5 are textbook days with a night between about −7 and −2 °C and a day between 4 and 9 °C. The best season since 1991 was 2020 (41 sap days); the leanest was 2003 (18).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at Cornwall (Daymet 1-km grid), scored with the same freeze-thaw rule as our live forecast. Ontario has no official season record, so they are a weather estimate. They describe a typical year at one point in the division; your sugarbush, slope and elevation can shift them by days.

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