Water Levels Forecast

Forecast of monthly mean lake levels for the next six months grouped as:

  • high level (thers a 5% probability of exceeding this level)
  • most probable level (there is a 50% probability of exceeding this level)
  • low level (thers a 95% probability of exceeding this level)

Canada/US flag Water levels are collected by CHS for the Canadian gauges and by NOS/NOAA for the American gauges. Six month forecasts of the probable range of future levels are prepared under the auspices of the International Coordinating Committee on Great Lakes Basic Hydraulic and Hydrologic Data by Environment Canada, Great Lakes-St. Lawrence Regulation Office in Cornwall and the U.S. Army Corps of Engineers, Detroit District.

Forecast Beginning 1 December

Monthly Mean Water Level IGLD 1985 (metres above Chart Datum IGLD 1985)

For Exceedence Probability Shown

LAKE SUPERIOR Most Probable LAC SUPÉRIEUR
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 183.68 (0.48) 183.66 (0.46) 183.64 (0.44) JANVIER
FEBRUARY 183.62 (0.42) 183.58 (0.38) 183.54 (0.34) FÉVRIER
MARCH 183.60 (0.40) 183.52 (0.32) 183.48 (0.28) MARS
APRIL 183.64 (0.44) 183.54 (0.34) 183.46 (0.26) AVRIL
MAY 183.74 (0.54) 183.62 (0.42) 183.49 (0.29) MAI
JUNE 183.84 (0.64) 183.69 (0.49) 183.54 (0.34) JUIN
(CHART DATUM 183.20 IGLD 1985) (ZÉRO DES CARTES 183.2 SRIGL 1985)
LAKE HURON Most Probable LAC HURON
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 176.75 (0.75) 176.71 (0.71) 176.69 (0.69) JANVIER
FEBRUARY 176.76 (0.76) 176.69 (0.69) 176.64 (0.64) FÉVRIER
MARCH 176.80 (0.80) 176.70 (0.70) 176.62 (0.62) MARS
APRIL 176.92 (0.92) 176.78 (0.78) 176.66 (0.66) AVRIL
MAY 177.04 (1.04) 176.87 (0.87) 176.71 (0.71) MAI
JUNE 177.14 (1.14) 176.94 (0.94) 176.76 (0.76) JUIN
(CHART DATUM 176.00 IGLD 1985) (ZÉRO DES CARTES 176.0 SRIGL 1985)
LAKE ST. CLAIR Most Probable LAC SAINTE-CLAIRE
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 175.44 (1.04) 175.33 (0.93) 175.17 (0.77) JANVIER
FEBRUARY 175.48 (1.08) 175.31 (0.91) 175.12 (0.72) FÉVRIER
MARCH 175.54 (1.14) 175.36 (0.96) 175.16 (0.76) MARS
APRIL 175.64 (1.24) 175.44 (1.04) 175.20 (0.80) AVRIL
MAY 175.70 (1.30) 175.52 (1.12) 175.27 (0.87) MAI
JUNE 175.77 (1.37) 175.56 (1.16) 175.32 (0.92) JUIN
(CHART DATUM 174.40 IGLD 1985) (ZÉRO DES CARTES 174.4 SRIGL 1985)
LAKE ERIE Most Probable LAC ÉRIÉ
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 174.50 (1.00) 174.36 (0.86) 174.30 (0.80) JANVIER
FEBRUARY 174.58 (1.08) 174.38 (0.88) 174.22 (0.72) FÉVRIER
MARCH 174.70 (1.20) 174.46 (0.96) 174.26 (0.76) MARS
APRIL 174.82 (1.32) 174.60 (1.10) 174.38 (0.88) AVRIL
MAY 174.88 (1.38) 174.67 (1.17) 174.41 (0.91) MAI
JUNE 174.91 (1.41) 174.68 (1.18) 174.42 (0.92) JUIN
(CHART DATUM 173.50 IGLD 1985) (ZÉRO DES CARTES 173.5 SRIGL 1985)
LAKE ONTARIO Most Probable LAC ONTARIO
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 75.01 (0.81) 74.82 (0.62) 74.74 (0.54) JANVIER
FEBRUARY 75.04 (0.84) 74.80 (0.60) 74.64 (0.44) FÉVRIER
MARCH 75.11 (0.91) 74.83 (0.63) 74.59 (0.39) MARS
APRIL 75.34 (1.14) 74.95 (0.75) 74.67 (0.47) AVRIL
MAY 75.44 (1.24) 75.01 (0.81) 74.72 (0.52) MAI
JUNE 75.50 (1.30) 75.00 (0.80) 74.77 (0.57) JUIN
(CHART DATUM  74.20 IGLD 1985) (ZÉRO DES CARTES 74.2 SRIGL 1985)
MONTREAL HARBOUR Most Probable PORT DE MONTRÉAL
MONTH 5% Probabilité Maximale 95% MOIS
JANUARY 7.09 (1.54) 6.49 (0.94) 5.92 (0.37) JANVIER
FEBRUARY 7.52 (1.97) 6.83 (1.28) 6.15 (0.60) FÉVRIER
MARCH 7.74 (2.19) 7.09 (1.54) 6.32 (0.77) MARS
APRIL 8.14 (2.59) 7.55 (2.00) 6.87 (1.32) AVRIL
MAY 8.48 (2.93) 7.42 (1.87) 6.43 (0.88) MAI
JUNE 7.98 (2.43) 6.91 (1.36) 5.91 (0.36) JUIN
(CHART DATUM   5.55 IGLD 1985) (ZÉRO DES CARTES 5.55 SRIGL 1985)