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Ontario · maple atlas

Maple sugaring in Leeds and Grenville, Ontario

Leeds and Grenville 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 77 farms reporting maple taps and 38,179 taps here. Around Brockville, sap usually runs from March 11 to April 11. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 155 days until the usual start.
Sap starts
Mar 11
weather estimate
Season ends
Apr 11
about 4 weeks
Sap days / season
32.9
1991–2025 average
Taps, 2021
38,179
#17 of 29 in ON

Sap-flow outlook at Brockville right now

Full Ontario forecast →

Forecast for Brockville, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Leeds and Grenville's season usually opens around March 11, which is 155 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° / 15°
    No refreeze forecast
  3. SatOct 10
    1° / 16°
    No refreeze forecast
  4. SunOct 11
    10° / 23°
    No refreeze forecast
  5. MonOct 12
    12° / 18°
    No refreeze forecast
  6. TueOct 13
    10° / 15°
    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 Brockville

Freeze-thaw weather at Brockville peaks in the weeks of Mar 2 to Apr 6, which hold about 47% 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 11 – Apr 110246Week of Dec 1: 1.4 sap days on averageWeek of Dec 8: 1.7 sap days on averageWeek of Dec 15: 1.1 sap days on averageWeek of Dec 22: 1.2 sap days on averageWeek of Dec 29: 1.0 sap days on averageWeek of Jan 5: 1.0 sap days on averageWeek of Jan 12: 0.7 sap days on averageWeek of Jan 19: 0.8 sap days on averageWeek of Jan 26: 0.7 sap days on averageWeek of Feb 2: 0.9 sap days on averageWeek of Feb 9: 1.0 sap days on averageWeek of Feb 16: 1.5 sap days on averageWeek of Feb 23: 1.5 sap days on averageWeek of Mar 2: 1.9 sap days on averageWeek of Mar 9: 2.2 sap days on averageWeek of Mar 16: 2.6 sap days on averageWeek of Mar 23: 3.0 sap days on averageWeek of Mar 30: 3.1 sap days on averageWeek of Apr 6: 2.6 sap days on averageWeek of Apr 13: 1.4 sap days on averageWeek of Apr 20: 1.1 sap days on averageWeek of Apr 27: 0.5 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: 0.0 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 11
Average number of freeze-thaw sap days in each week of the season at Brockville, 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 11; the middle half of seasons fell between Mar 4 and Mar 17. Earliest Feb 15 (2012), latest Mar 21 (2018).
Closing signal
Median Apr 11; middle half between Apr 7 and Apr 16. Earliest Mar 12 (2012), latest Apr 23 (2018).
Sap days by month
Dec17%Jan11%Feb15%Mar33%Apr23%May0%

35 seasons of sap weather

Leeds and Grenville seasons, 1991–2025

The best sap year at Brockville was 2012 with 45 freeze-thaw days; the leanest was 2010 with 22. 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 9 – Apr 10, 30 sap days3020242024: Feb 21 – Mar 27, 29 sap days2920232023: Mar 9 – Apr 9, 40 sap days4020222022: Mar 8 – Apr 11, 42 sap days4220212021: Mar 2 – Apr 6, 28 sap days2820202020: Mar 1 – Apr 2, 45 sap days4520192019: Mar 18 – Apr 17, 39 sap days3920182018: Mar 21 – Apr 23, 41 sap days4120172017: Mar 18 – Apr 8, 29 sap days2920162016: Mar 11 – Apr 15, 38 sap days3820152015: Mar 17 – Apr 16, 22 sap days2220142014: Mar 18 – Apr 20, 27 sap days2720132013: Mar 13 – Apr 15, 37 sap days3720122012: Feb 15 – Mar 12, 45 sap days4520112011: Mar 10 – Apr 9, 27 sap days2720102010: Mar 2 – Mar 28, 22 sap days2220092009: Mar 11 – Apr 14, 34 sap days3420082008: Mar 14 – Apr 16, 30 sap days3020072007: Mar 10 – Apr 11, 34 sap days3420062006: Mar 5 – Apr 9, 36 sap days3620052005: Mar 13 – Apr 16, 40 sap days4020042004: Mar 14 – Apr 17, 29 sap days2920032003: Mar 16 – Apr 18, 24 sap days2420022002: Mar 8 – Apr 7, 35 sap days3520012001: Mar 18 – Apr 19, 27 sap days2720002000: Feb 22 – Mar 28, 32 sap days3219991999: Mar 9 – Apr 12, 41 sap days4119981998: Feb 26 – Mar 25, 28 sap days2819971997: Mar 20 – Apr 15, 27 sap days2719961996: Mar 17 – Apr 19, 36 sap days3619951995: Feb 27 – Apr 3, 38 sap days3819941994: Mar 15 – Apr 12, 27 sap days2719931993: Mar 13 – Apr 7, 28 sap days2819921992: Mar 19 – Apr 17, 28 sap days2819911991: Mar 3 – Apr 4, 37 sap days37
Each bar runs from the season's opening signal to its closing signal, estimated from daily Daymet temperatures at Brockville. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Leeds and Grenville 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 77 in Leeds and Grenville, with 38,179 taps; in 2016, 112 farms and 49,964 taps. Among Ontario's 29 census divisions with a published tap count, Leeds and Grenville ranks 17th, and 81st of the 94 in this atlas.

Over the five years the farm count changed −31% and taps −24%. 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.

Leeds and Grenville maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
20217738,179E
201611249,964
  • 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 Brockville, the division's most populous municipality in the 2021 Census; the cell sits at 86 m (282 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

Leeds and Grenville sugaring questions

When should I tap maple trees in Leeds and Grenville, Ontario?
In a typical year the sap starts running around March 11 near Brockville and the season winds down around April 11. 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 15 and as late as Mar 21.
How much maple syrup does Leeds and Grenville produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 77 farms reporting 38,179 maple taps in Leeds and Grenville, number 17 of 29 Ontario divisions with a published count.
How many sap days does Leeds and Grenville get in a season?
On average 32.9 freeze-thaw sap days from December through May at Brockville, of which about 13 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 (45 sap days); the leanest was 2010 (22).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at Brockville (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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