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Ontario · maple atlas

Maple sugaring in Lanark, Ontario

Lanark is a county in Ontario. Ontario's census divisions are its counties, districts and regional municipalities. Statistics Canada's 2021 Census of Agriculture counted 89 farms reporting maple taps and 208,832 taps here, number 3 in Ontario. Around Mississippi Mills, sap usually runs from March 15 to April 16. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 159 days until the usual start.
Sap starts
Mar 15
weather estimate
Season ends
Apr 16
about 5 weeks
Sap days / season
30.5
1991–2025 average
Taps, 2021
208,832
#3 of 29 in ON

Sap-flow outlook at Mississippi Mills right now

Full Ontario forecast →

Forecast for Mississippi Mills, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Lanark's season usually opens around March 15, which is 159 days away.

No freeze-thaw days in the forecast

freeze thaw 0 °C

  1. ThuOct 8
    8° / 16°
    No refreeze forecast
  2. FriOct 9
    5° / 14°
    No refreeze forecast
  3. SatOct 10
    1° / 15°
    No refreeze forecast
  4. SunOct 11
    12° / 23°
    No refreeze forecast
  5. MonOct 12
    11° / 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 Mississippi Mills

Freeze-thaw weather at Mississippi Mills peaks in the weeks of Mar 9 to Apr 13, which hold about 50% 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 15 – Apr 160246Week of Dec 1: 0.9 sap days on averageWeek of Dec 8: 1.1 sap days on averageWeek of Dec 15: 0.8 sap days on averageWeek of Dec 22: 0.8 sap days on averageWeek of Dec 29: 0.6 sap days on averageWeek of Jan 5: 0.6 sap days on averageWeek of Jan 12: 0.4 sap days on averageWeek of Jan 19: 0.5 sap days on averageWeek of Jan 26: 0.5 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: 1.0 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: 1.9 sap days on averageWeek of Mar 16: 2.3 sap days on averageWeek of Mar 23: 2.8 sap days on averageWeek of Mar 30: 3.1 sap days on averageWeek of Apr 6: 3.1 sap days on averageWeek of Apr 13: 2.0 sap days on averageWeek of Apr 20: 1.6 sap days on averageWeek of Apr 27: 1.2 sap days on averageWeek of May 4: 0.4 sap days on averageWeek of May 11: 0.2 sap days on averageWeek of May 18: 0.1 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 15
Average number of freeze-thaw sap days in each week of the season at Mississippi Mills, 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 15; the middle half of seasons fell between Mar 10 and Mar 21. Earliest Feb 26 (2010), latest Mar 29 (2015).
Closing signal
Median Apr 16; middle half between Apr 11 and Apr 19. Earliest Mar 13 (2012), latest Apr 26 (1996).
Sap days by month
Dec13%Jan7%Feb12%Mar32%Apr32%May3%

35 seasons of sap weather

Lanark seasons, 1991–2025

The best sap year at Mississippi Mills was 2020 with 52 freeze-thaw days; the leanest was 2015 with 16. 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 18 – Apr 21, 30 sap days3020242024: Mar 3 – Apr 3, 34 sap days3420232023: Mar 11 – Apr 10, 42 sap days4220222022: Mar 10 – Apr 11, 35 sap days3520212021: Mar 4 – Apr 6, 26 sap days2620202020: Mar 9 – Apr 13, 52 sap days5220192019: Mar 22 – Apr 17, 27 sap days2720182018: Mar 26 – Apr 23, 36 sap days3620172017: Mar 11 – Apr 14, 27 sap days2720162016: Mar 16 – Apr 16, 37 sap days3720152015: Mar 29 – Apr 19, 16 sap days1620142014: Mar 21 – Apr 20, 22 sap days2220132013: Mar 15 – Apr 15, 28 sap days2820122012: Mar 3 – Mar 13, 30 sap days3020112011: Mar 18 – Apr 22, 22 sap days2220102010: Feb 26 – Mar 30, 30 sap days3020092009: Mar 13 – Apr 17, 30 sap days3020082008: Mar 28 – Apr 16, 18 sap days1820072007: Mar 15 – Apr 11, 26 sap days2620062006: Mar 9 – Apr 11, 28 sap days2820052005: Mar 14 – Apr 16, 37 sap days3720042004: Mar 16 – Apr 17, 30 sap days3020032003: Mar 18 – Apr 18, 22 sap days2220022002: Mar 13 – Apr 11, 41 sap days4120012001: Mar 20 – Apr 20, 31 sap days3120002000: Feb 27 – Apr 2, 31 sap days3119991999: Mar 15 – Apr 15, 36 sap days3619981998: Mar 6 – Apr 10, 27 sap days2719971997: Mar 28 – Apr 20, 22 sap days2219961996: Mar 23 – Apr 26, 38 sap days3819951995: Mar 14 – Apr 18, 40 sap days4019941994: Mar 20 – Apr 23, 34 sap days3419931993: Mar 23 – Apr 14, 23 sap days2319921992: Mar 26 – Apr 19, 25 sap days2519911991: Mar 7 – Apr 11, 33 sap days33
Each bar runs from the season's opening signal to its closing signal, estimated from daily Daymet temperatures at Mississippi Mills. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Lanark 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 89 in Lanark, with 208,832 taps; in 2016, 107 farms and 147,710 taps. Among Ontario's 29 census divisions with a published tap count, Lanark ranks 3rd, and 46th of the 94 in this atlas.

Over the five years the farm count changed −17% and taps +41%. 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.

Lanark maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
202189208,832
2016107147,710

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 Mississippi Mills, the division's most populous municipality in the 2021 Census; the cell sits at 119 m (390 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

Lanark sugaring questions

When should I tap maple trees in Lanark, Ontario?
In a typical year the sap starts running around March 15 near Mississippi Mills and the season winds down around April 16. 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 26 and as late as Mar 29.
How much maple syrup does Lanark produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 89 farms reporting 208,832 maple taps in Lanark, number 3 of 29 Ontario divisions with a published count.
How many sap days does Lanark get in a season?
On average 30.5 freeze-thaw sap days from December through May at Mississippi Mills, of which about 10.8 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 (52 sap days); the leanest was 2015 (16).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at Mississippi Mills (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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