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Ontario · maple atlas

Maple sugaring in Frontenac, Ontario

Frontenac is a county in Ontario. Ontario's census divisions are its counties, districts and regional municipalities. Statistics Canada's 2021 Census of Agriculture counted 45 farms reporting maple taps and 22,101 taps here. Around Kingston, sap usually runs from March 10 to April 11. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 154 days until the usual start.
Sap starts
Mar 10
weather estimate
Season ends
Apr 11
about 5 weeks
Sap days / season
32.5
1991–2025 average
Taps, 2021
22,101
#21 of 29 in ON

Sap-flow outlook at Kingston right now

Full Ontario forecast →

Forecast for Kingston, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Frontenac's season usually opens around March 10, which is 154 days away.

No freeze-thaw days in the forecast

freeze thaw 0 °C

  1. ThuOct 8
    9° / 17°
    No refreeze forecast
  2. FriOct 9
    7° / 18°
    No refreeze forecast
  3. SatOct 10
    3° / 18°
    No refreeze forecast
  4. SunOct 11
    14° / 22°
    No refreeze forecast
  5. MonOct 12
    12° / 19°
    No refreeze forecast
  6. TueOct 13
    11° / 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 Kingston

Freeze-thaw weather at Kingston peaks in the weeks of Mar 9 to Apr 6, which hold about 40% 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 10 – Apr 110246Week of Dec 1: 1.5 sap days on averageWeek of Dec 8: 1.6 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: 1.1 sap days on averageWeek of Jan 5: 1.1 sap days on averageWeek of Jan 12: 0.7 sap days on averageWeek of Jan 19: 0.9 sap days on averageWeek of Jan 26: 0.6 sap days on averageWeek of Feb 2: 1.0 sap days on averageWeek of Feb 9: 0.9 sap days on averageWeek of Feb 16: 1.6 sap days on averageWeek of Feb 23: 1.6 sap days on averageWeek of Mar 2: 1.7 sap days on averageWeek of Mar 9: 2.1 sap days on averageWeek of Mar 16: 2.5 sap days on averageWeek of Mar 23: 2.9 sap days on averageWeek of Mar 30: 3.0 sap days on averageWeek of Apr 6: 2.6 sap days on averageWeek of Apr 13: 1.3 sap days on averageWeek of Apr 20: 0.9 sap days on averageWeek of Apr 27: 0.6 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 10
Average number of freeze-thaw sap days in each week of the season at Kingston, 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 10; the middle half of seasons fell between Mar 3 and Mar 16. Earliest Feb 14 (2012), latest Mar 20 (1992).
Closing signal
Median Apr 11; middle half between Apr 5 and Apr 16. Earliest Mar 12 (2012), latest Apr 23 (2018).
Sap days by month
Dec18%Jan12%Feb15%Mar32%Apr23%May1%

35 seasons of sap weather

Frontenac seasons, 1991–2025

The best sap year at Kingston was 2020 with 47 freeze-thaw days; the leanest was 2008 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 11 – Apr 10, 30 sap days3020242024: Feb 20 – Mar 26, 29 sap days2920232023: Mar 8 – Apr 10, 38 sap days3820222022: Mar 7 – Apr 11, 37 sap days3720212021: Mar 3 – Apr 6, 28 sap days2820202020: Feb 28 – Apr 3, 47 sap days4720192019: Mar 16 – Apr 17, 39 sap days3920182018: Mar 20 – Apr 23, 41 sap days4120172017: Mar 4 – Apr 8, 30 sap days3020162016: Feb 27 – Apr 3, 31 sap days3120152015: Mar 16 – Apr 16, 28 sap days2820142014: Mar 17 – Apr 20, 27 sap days2720132013: Mar 13 – Apr 15, 40 sap days4020122012: Feb 14 – Mar 12, 44 sap days4420112011: Mar 10 – Apr 9, 24 sap days2420102010: Mar 2 – Mar 30, 24 sap days2420092009: Mar 11 – Apr 14, 31 sap days3120082008: Mar 12 – Apr 16, 19 sap days1920072007: Mar 10 – Apr 11, 28 sap days2820062006: Feb 28 – Apr 2, 39 sap days3920052005: Mar 11 – Apr 12, 36 sap days3620042004: Mar 13 – Apr 17, 30 sap days3020032003: Mar 16 – Apr 17, 25 sap days2520022002: Mar 6 – Apr 7, 39 sap days3920012001: Mar 17 – Apr 19, 26 sap days2620002000: Feb 20 – Mar 25, 33 sap days3319991999: Mar 6 – Apr 6, 43 sap days4319981998: Feb 26 – Mar 25, 31 sap days3119971997: Mar 18 – Apr 15, 26 sap days2619961996: Mar 18 – Apr 16, 34 sap days3419951995: Mar 5 – Apr 8, 42 sap days4219941994: Mar 15 – Apr 12, 30 sap days3019931993: Mar 14 – Apr 14, 26 sap days2619921992: Mar 20 – Apr 16, 25 sap days2519911991: 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 Kingston. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Frontenac 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 45 in Frontenac, with 22,101 taps; in 2016, 59 farms and 20,548 taps. Among Ontario's 29 census divisions with a published tap count, Frontenac ranks 21st, and 86th of the 94 in this atlas.

Over the five years the farm count changed −24% and taps +8%. 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.

Frontenac maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
20214522,101E
20165920,548
  • 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 Kingston, the division's most populous municipality in the 2021 Census; the cell sits at 89 m (292 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

Frontenac sugaring questions

When should I tap maple trees in Frontenac, Ontario?
In a typical year the sap starts running around March 10 near Kingston 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 14 and as late as Mar 20.
How much maple syrup does Frontenac produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 45 farms reporting 22,101 maple taps in Frontenac, number 21 of 29 Ontario divisions with a published count.
How many sap days does Frontenac get in a season?
On average 32.5 freeze-thaw sap days from December through May at Kingston, of which about 14.2 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 (47 sap days); the leanest was 2008 (19).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at Kingston (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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