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Ontario · maple atlas

Maple sugaring in Grey, Ontario

Grey is a county in Ontario. Ontario's census divisions are its counties, districts and regional municipalities. Statistics Canada's 2021 Census of Agriculture counted 198 farms reporting maple taps and 210,348 taps here, number 2 in Ontario. Around Owen Sound, sap usually runs from March 14 to April 15. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 158 days until the usual start.
Sap starts
Mar 14
weather estimate
Season ends
Apr 15
about 5 weeks
Sap days / season
26.7
1991–2025 average
Taps, 2021
210,348
#2 of 29 in ON

Sap-flow outlook at Owen Sound right now

Full Ontario forecast →

Forecast for Owen Sound, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Grey's season usually opens around March 14, which is 158 days away.

No freeze-thaw days in the forecast

freeze thaw 0 °C

  1. ThuOct 8
    8° / 16°
    No refreeze forecast
  2. FriOct 9
    4° / 15°
    No refreeze forecast
  3. SatOct 10
    4° / 22°
    No refreeze forecast
  4. SunOct 11
    17° / 24°
    No refreeze forecast
  5. MonOct 12
    12° / 18°
    No refreeze forecast
  6. TueOct 13
    12° / 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 Owen Sound

Freeze-thaw weather at Owen Sound peaks in the weeks of Mar 2 to Apr 13, which hold about 51% 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 14 – Apr 150246Week of Dec 1: 0.7 sap days on averageWeek of Dec 8: 1.0 sap days on averageWeek of Dec 15: 1.1 sap days on averageWeek of Dec 22: 1.1 sap days on averageWeek of Dec 29: 0.7 sap days on averageWeek of Jan 5: 0.7 sap days on averageWeek of Jan 12: 0.5 sap days on averageWeek of Jan 19: 0.6 sap days on averageWeek of Jan 26: 0.4 sap days on averageWeek of Feb 2: 0.7 sap days on averageWeek of Feb 9: 0.8 sap days on averageWeek of Feb 16: 1.3 sap days on averageWeek of Feb 23: 1.3 sap days on averageWeek of Mar 2: 1.5 sap days on averageWeek of Mar 9: 1.6 sap days on averageWeek of Mar 16: 2.1 sap days on averageWeek of Mar 23: 2.5 sap days on averageWeek of Mar 30: 2.1 sap days on averageWeek of Apr 6: 2.1 sap days on averageWeek of Apr 13: 1.9 sap days on averageWeek of Apr 20: 1.2 sap days on averageWeek of Apr 27: 0.8 sap days on averageWeek of May 4: 0.1 sap days on averageWeek of May 11: 0.1 sap days on averageWeek of May 18: 0.1 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 14
Average number of freeze-thaw sap days in each week of the season at Owen Sound, 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 14; the middle half of seasons fell between Mar 7 and Mar 20. Earliest Feb 12 (2012), latest Apr 9 (2003).
Closing signal
Median Apr 15; middle half between Apr 6 and Apr 17. Earliest Mar 11 (2012), latest Apr 26 (1996).
Sap days by month
Dec15%Jan9%Feb15%Mar32%Apr27%May1%

35 seasons of sap weather

Grey seasons, 1991–2025

The best sap year at Owen Sound was 2012 with 38 freeze-thaw days; the leanest was 2007 with 19. 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 14 – Apr 17, 29 sap days2920242024: Feb 21 – Mar 26, 30 sap days3020232023: Mar 9 – Apr 9, 37 sap days3720222022: Mar 18 – Apr 18, 30 sap days3020212021: Mar 2 – Apr 4, 27 sap days2720202020: Mar 7 – Apr 7, 36 sap days3620192019: Mar 18 – Apr 17, 25 sap days2520182018: Mar 26 – Apr 22, 20 sap days2020172017: Mar 1 – Mar 29, 21 sap days2120162016: Mar 13 – Apr 15, 25 sap days2520152015: Mar 20 – Apr 15, 19 sap days1920142014: Mar 27 – Apr 24, 20 sap days2020132013: Mar 14 – Apr 17, 20 sap days2020122012: Feb 12 – Mar 11, 38 sap days3820112011: Mar 19 – Apr 22, 23 sap days2320102010: Mar 6 – Mar 31, 22 sap days2220092009: Mar 13 – Apr 17, 34 sap days3420082008: Mar 26 – Apr 16, 21 sap days2120072007: Mar 11 – Apr 15, 19 sap days1920062006: Mar 7 – Apr 9, 20 sap days2020052005: Mar 19 – Apr 16, 26 sap days2620042004: Mar 14 – Apr 16, 31 sap days3120032003: Apr 9 – Apr 17, 25 sap days2520022002: Mar 9 – Apr 10, 31 sap days3120012001: Mar 16 – Apr 19, 25 sap days2520002000: Feb 17 – Mar 20, 27 sap days2719991999: Mar 2 – Apr 5, 34 sap days3419981998: Feb 24 – Mar 25, 26 sap days2619971997: Mar 21 – Apr 19, 26 sap days2619961996: Mar 23 – Apr 26, 29 sap days2919951995: Mar 18 – Apr 11, 32 sap days3219941994: Mar 20 – Apr 12, 23 sap days2319931993: Mar 18 – Apr 22, 29 sap days2919921992: Mar 20 – Apr 16, 25 sap days2519911991: Mar 3 – Apr 3, 31 sap days31
Each bar runs from the season's opening signal to its closing signal, estimated from daily Daymet temperatures at Owen Sound. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Grey 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 198 in Grey, with 210,348 taps; in 2016, 225 farms and 139,192 taps. Among Ontario's 29 census divisions with a published tap count, Grey ranks 2nd, and 45th of the 94 in this atlas.

Over the five years the farm count changed −12% and taps +51%. 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.

Grey maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
2021198210,348
2016225139,192

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 Owen Sound, the division's most populous municipality in the 2021 Census; the cell sits at 192 m (630 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

Grey sugaring questions

When should I tap maple trees in Grey, Ontario?
In a typical year the sap starts running around March 14 near Owen Sound and the season winds down around April 15. 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 12 and as late as Apr 9.
How much maple syrup does Grey produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 198 farms reporting 210,348 maple taps in Grey, number 2 of 29 Ontario divisions with a published count.
How many sap days does Grey get in a season?
On average 26.7 freeze-thaw sap days from December through May at Owen Sound, of which about 12 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 2012 (38 sap days); the leanest was 2007 (19).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at Owen Sound (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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