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Ontario · maple atlas

Maple sugaring in Middlesex, Ontario

Middlesex is a county in Ontario. Ontario's census divisions are its counties, districts and regional municipalities. Statistics Canada's 2021 Census of Agriculture counted 53 farms reporting maple taps and 39,170 taps here. Around London, sap usually runs from March 5 to April 4. Here's the long-run pattern, 35 seasons of sap weather, and the outlook this week.
Too early to tapAbout 149 days until the usual start.
Sap starts
Mar 5
weather estimate
Season ends
Apr 4
about 4 weeks
Sap days / season
29.8
1991–2025 average
Taps, 2021
39,170
#15 of 29 in ON

Sap-flow outlook at London right now

Full Ontario forecast →

Forecast for London, ON

Updated Oct 7, 11:00 AM EDT

Off-season for now. Sap needs freezing nights, and none are in sight. Middlesex's season usually opens around March 5, which is 149 days away.

No freeze-thaw days in the forecast

freeze thaw 0 °C

  1. ThuOct 8
    8° / 18°
    No refreeze forecast
  2. FriOct 9
    4° / 18°
    No refreeze forecast
  3. SatOct 10
    7° / 24°
    No refreeze forecast
  4. SunOct 11
    15° / 23°
    No refreeze forecast
  5. MonOct 12
    13° / 20°
    No refreeze forecast
  6. TueOct 13
    13° / 17°
    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 London

Freeze-thaw weather at London peaks in the weeks of Mar 2 to Apr 6, which hold about 44% 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 5 – Apr 40246Week of Dec 1: 1.3 sap days on averageWeek of Dec 8: 1.5 sap days on averageWeek of Dec 15: 1.2 sap days on averageWeek of Dec 22: 1.0 sap days on averageWeek of Dec 29: 0.7 sap days on averageWeek of Jan 5: 0.9 sap days on averageWeek of Jan 12: 0.7 sap days on averageWeek of Jan 19: 0.6 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: 1.1 sap days on averageWeek of Feb 16: 1.5 sap days on averageWeek of Feb 23: 1.4 sap days on averageWeek of Mar 2: 1.8 sap days on averageWeek of Mar 9: 1.9 sap days on averageWeek of Mar 16: 2.6 sap days on averageWeek of Mar 23: 2.4 sap days on averageWeek of Mar 30: 2.5 sap days on averageWeek of Apr 6: 1.9 sap days on averageWeek of Apr 13: 1.4 sap days on averageWeek of Apr 20: 1.0 sap days on averageWeek of Apr 27: 0.6 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: 0.1 sap days on averageWeek of May 25: 0.0 sap days on averageDecJanFebMarAprMaytaps in ~Mar 5
Average number of freeze-thaw sap days in each week of the season at London, 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 5; the middle half of seasons fell between Feb 28 and Mar 13. Earliest Feb 6 (2024), latest Apr 9 (2003).
Closing signal
Median Apr 4; middle half between Mar 29 and Apr 8. Earliest Mar 7 (2000), latest Apr 22 (2018).
Sap days by month
Dec18%Jan10%Feb17%Mar33%Apr21%May2%

35 seasons of sap weather

Middlesex seasons, 1991–2025

The best sap year at London was 2020 with 49 freeze-thaw days; the leanest was 2011 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: Feb 27 – Apr 1, 28 sap days2820242024: Feb 6 – Mar 12, 30 sap days3020232023: Mar 1 – Apr 3, 38 sap days3820222022: Mar 7 – Apr 4, 38 sap days3820212021: Feb 23 – Mar 21, 33 sap days3320202020: Feb 24 – Mar 24, 49 sap days4920192019: Mar 8 – Apr 4, 37 sap days3720182018: Mar 19 – Apr 22, 36 sap days3620172017: Feb 14 – Mar 21, 27 sap days2720162016: Feb 17 – Mar 23, 40 sap days4020152015: Mar 13 – Apr 5, 25 sap days2520142014: Mar 15 – Apr 19, 24 sap days2420132013: Mar 12 – Apr 8, 33 sap days3320122012: Feb 11 – Mar 11, 38 sap days3820112011: Mar 9 – Apr 7, 16 sap days1620102010: Mar 3 – Mar 31, 18 sap days1820092009: Mar 4 – Apr 8, 38 sap days3820082008: Mar 14 – Apr 6, 25 sap days2520072007: Mar 9 – Mar 30, 21 sap days2120062006: Mar 24 – Mar 30, 26 sap days2620052005: Mar 6 – Apr 8, 20 sap days2020042004: Mar 4 – Apr 7, 27 sap days2720032003: Apr 9 – Apr 13, 22 sap days2220022002: Mar 5 – Apr 7, 43 sap days4320012001: Mar 8 – Apr 5, 26 sap days2620002000: Mar 1 – Mar 7, 27 sap days2719991999: Feb 28 – Mar 30, 37 sap days3719981998: Feb 21 – Mar 25, 27 sap days2719971997: Mar 1 – Apr 4, 32 sap days3219961996: Mar 15 – Apr 11, 25 sap days2519951995: Feb 21 – Mar 27, 32 sap days3219941994: Mar 15 – Apr 11, 25 sap days2519931993: Mar 11 – Apr 14, 23 sap days2319921992: Mar 15 – Apr 16, 29 sap days2919911991: Mar 1 – Apr 3, 28 sap days28
Each bar runs from the season's opening signal to its closing signal, estimated from daily Daymet temperatures at London. Dashed lines mark the typical dates. The right column counts freeze-thaw sap days from December through May.

Maple production

Middlesex 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 53 in Middlesex, with 39,170 taps; in 2016, 65 farms and 61,644 taps. Among Ontario's 29 census divisions with a published tap count, Middlesex ranks 15th, and 79th of the 94 in this atlas.

Over the five years the farm count changed −18% and taps −36%. 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.

Middlesex maple production, 2016 and 2021 (Statistics Canada, Census of Agriculture)
Census yearFarms reporting tapsTaps
20215339,170E
20166561,644
  • 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 London, the division's most populous municipality in the 2021 Census; the cell sits at 255 m (837 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

Middlesex sugaring questions

When should I tap maple trees in Middlesex, Ontario?
In a typical year the sap starts running around March 5 near London and the season winds down around April 4. 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 6 and as late as Apr 9.
How much maple syrup does Middlesex produce?
Statistics Canada doesn't publish syrup volume by census division. Its 2021 Census of Agriculture counted 53 farms reporting 39,170 maple taps in Middlesex, number 15 of 29 Ontario divisions with a published count.
How many sap days does Middlesex get in a season?
On average 29.8 freeze-thaw sap days from December through May at London, of which about 13.2 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 (49 sap days); the leanest was 2011 (16).
Where do these dates come from?
From 35 seasons of daily high and low temperatures at London (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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