Precipitation Change in Canada

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Changes in climate variables such as temperature, precipitation and humidity affect a wide range of natural processes and human activities. Globally, while annual average precipitation varies greatly from region to region, precipitation at land-based stations has been near the reference valueFootnote [1],Footnote [2] for the third consecutive year. In 2014, global precipitation was 0.52 millimetres or 0.05% below the 1961–1990 reference value.

Annual average precipitation in Canada for the year 2014 was 2% below the 1961–1990 reference value.Footnote [3] However, the climate tended to be wetter from the mid-1970s onward, as shown by an ever increasing nine-year moving average, with the wettest year being 2005, at 16% above the reference value. In contrast, Canada's driest year on record was 1956 at 12% below the reference value. Regional patterns vary greatly however (see Regional precipitation change).

Annual average precipitation departures from 1961–1990 reference value, Canada, 1948 to 2014

Graph

Long description

The markers show the annual average precipitation departures in percentage difference from the 1961–1990 reference value over the period 1948 to 2014. A line is also displayed showing the nine-year moving average. During this period, the wettest year was 2005, while the driest year was 1956. A dash line at zero on the y-axis represents the 1961–1990 reference value.

Data for this chart
Annual average precipitation departures from 1961–1990 reference value, Canada, 1948 to 2014
YearPrecipitation departures
(percentage)
Wettest year ranking
1948-10.462
1949-10.865
1950-10.161
1951-9.057
1952-9.459
1953-6.756
1954-9.460
1955-10.664
1956-12.267
1957-10.966
1958-10.563
1959-4.052
1960-5.855
1961-9.058
1962-4.153
1963-2.347
1964-1.042
1965-5.154
1966-2.348
1967-3.350
1968-0.841
1969-4.051
1970-0.140
19712.925
1972-2.045
19734.218
19744.119
19750.238
1976-0.139
19772.327
1978-3.249
19791.831
19802.426
19814.517
19822.030
19833.422
19843.421
19852.924
19860.836
19870.737
19886.011
1989-1.544
19904.816
19917.18
19920.935
19931.832
19941.034
19952.228
19969.83
19975.214
1998-1.043
19997.17
20003.323
20011.033
20022.129
20035.613
20045.812
200515.61
20063.720
20079.44
20086.210
20094.915
201010.72
20118.76
20129.15
20136.39
2014-2.246

Download data file (Excel/CSV; 1.66 KB)

How this indicator was calculated

Note: Annual average precipitation departures were computed for weather stations across Canada with sufficiently long data records to allow for trend calculation and were then interpolated to a 50-kilometre spaced grid. Annual grid points values were averaged together to produce an annual time series of precipitation departures representing the entire country.
Source: Environment and Climate Change Canada (2015) Adjusted and Homogenized Canadian Climate Data (AHCCD).

Seasonal precipitation change

During the past 67 years (1948–2014), the seasonal average precipitation departures for Canada have shown an overall upward progression for each of the four seasons (as illustrated by the nine-year moving average lines in the charts below). All seasons tended to be wetter than the corresponding 1961–1990 reference value from the mid-1970s onward. The wettest winter recorded occurred in 2011,Footnote [4] while the wettest spring, summer and fall were in 2012, 2005 and 2010, respectively. The driest seasons recorded were all in the 1950s (winter 1957, spring 1956, summer 1958 and fall 1952).

Seasonal average precipitation departures from the 1961–1990 reference value, Canada, 1948 to 2014

Graphs

Long description

The markers show the seasonal average precipitation departures in percentage over the period 1948 to 2014 for winter (top-left chart), spring (top-right chart), summer (bottom-left chart) and fall (bottom-right chart). The seasonal Canadian reference value is shown with a dashed line in each chart. A nine-year moving average line is also displayed showing an overall upward progression for each of the four seasons.

Data for this chart
Seasonal average precipitation departures from the 1961–1990 reference value, Canada, 1948 to 2014
YearWinter precipitation departure
(percentage)
Spring precipitation departure
(percentage)
Summer precipitation departure
(percentage)
Fall precipitation departure
(percentage)
1948-15.1-10.30.7-19.8
1949-17.3-16.1-6.5-10.1
1950-13.0-24.2-9.3-9.3
1951-4.7-2.0-10.5-7.4
1952-16.8-10.53.9-23.3
1953-8.1-7.81.3-18.1
1954-13.6-15.0-5.6-12.6
1955-13.5-8.5-9.7-11.1
1956-1.9-27.1-4.9-18.8
1957-20.2-20.9-2.3-10.3
19585.3-14.8-14.0-7.1
1959-13.0-5.2-3.76.1
1960-5.6-8.7-2.7-6.0
1961-14.1-10.3-12.8-5.1
1962-4.2-9.53.8-12.5
19633.7-14.77.2-8.1
1964-4.41.22.3-7.7
196512.3-12.6-6.5-5.6
1966-15.6-5.6-1.00.4
1967-2.6-10.1-5.2-1.6
19685.4-2.4-4.33.9
19694.7-11.5-2.2-1.0
1970-6.8-6.10.15.2
19714.3-4.1-2.38.7
19721.55.1-6.3-2.8
1973-9.7-0.15.26.8
19741.45.13.0-2.6
1975-1.5-4.52.3-0.6
19764.34.33.5-18.1
197715.216.8-4.4-1.7
1978-10.8-0.51.9-1.1
1979-9.720.4-1.4-3.1
19804.92.26.80.9
19816.65.71.89.8
1982-1.11.3-1.10.4
19831.42.50.57.5
19840.5-1.47.15.7
1985-0.2-1.90.98.3
19866.714.3-0.4-2.4
19871.80.73.7-5.9
19882.211.27.16.7
1989-7.1-2.2-7.58.6
1990-1.47.7-0.88.1
19912.76.88.612.0
199211.97.7-8.37.0
1993-3.30.211.2-2.5
1994-4.88.5-0.72.0
1995-1.9-0.60.18.2
199615.34.05.310.2
199718.00.810.45.3
1998-4.5-8.9-1.01.7
19999.015.34.40.3
2000-0.12.48.9-2.5
2001-0.912.11.1-4.5
2002-4.3-0.312.6-3.7
20031.88.91.310.1
20048.510.5-5.110.0
200519.116.814.512.9
200610.714.1-5.35.5
2007-0.710.05.211.5
200811.3-3.810.9-0.2
200914.24.74.34.2
2010-2.34.57.114.5
201128.2-3.412.01.8
20125.920.04.411.2
20135.44.51.81.0
2014-14.81.45.8-1.5

Download data file (Excel/CSV; 2.80 KB)

How this indicator was calculated

Note: Seasonal average precipitation departures were computed for weather stations across Canada with sufficiently long data records to allow for trend calculation and were then interpolated to a 50-kilometre spaced grid. Annual grid point values were averaged together to produce an annual time series of precipitation departures representing the entire country. Seasons are defined as winter (December of previous year, January and February), spring (March, April and May), summer (June, July and August) and fall (September, October, and November). The seasonal average precipitation departures for 2014 are based on preliminary data.
Source: Environment and Climate Change Canada (2015) Adjusted and Homogenized Canadian Climate Data (AHCCD).

Regional precipitation change

In 2014, while annual average precipitation in the country as a whole was 2% below the Canadian 1961–1990 reference value, southern Saskatchewan and some areas in Ontario had wetter conditions than the reference value while most of Yukon, Northwest Territories and part of Nunavut (Ellesmere Island) had drier conditions. The rest of the country had average precipitation departures near the reference value.

Regional average precipitation departures from 1961–1990 reference value, Canada, 2014

Map

Long description

The map shows the average precipitation departures from the 1961–1990 reference value in percentage for the year 2014.

How this indicator was calculated

Note: Annual average precipitation departures were computed for 464 weather stations across Canada and were then interpolated to a 50-kilometre spaced grid.
Source: Environment and Climate Change Canada (2016) Canadian Gridded Temperature and Precipitation Anomalies (CANGRD).

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