Temperature & Precipitation in Historical Perspective
Spring 2002
National Temperature
The
Canadian climate certainly can be interesting. After 19
consecutive seasons of above normal temperatures, Canada finally experienced
a cooler than normal spring (March, April, and May). In fact,
Canada, as a whole, had its 5th coolest spring, since comparable nationwide records began in
1948, at 1.4°C below normal,
based on preliminary
data. The map to the right shows that most of
Canada had temperatures more than 1°C below normal, with parts of northern
Saskatchewan and Alberta experiencing temperature as cold as 5°C below
normal. Vancouver Island, southern Ontario, southern Quebec, the
Maritimes, and most of the Arctic islands had temperatures near normal this spring. Only northern Yukon and Northwest Territories
experienced warmer than normal temperatures this spring.
The
chart to the left shows what a difference a year
makes. The previous four springs were among the warmest on record, and
this spring was among the coolest. However, springs historically, have continued
to get warmer, with a warming of 1.4°C over the 55-year period, as shown by the
dashed red line in the chart. The national warmest/coolest temperature table lists
the
ten coolest and warmest springs for the entire country. The coolest spring
continues to be 1974 (-1.8°C), and the warmest was 1998 (+3.2°C). The national
temperature departures table shows the full list of years in the order from
warmest to coolest one.
National Precipitation
As a whole,
Canada had a wetter than normal spring. Spring 2002 was the 18th wettest out
of the 54-year period of record, 5.6% above normal, based on preliminary data.
But, this summary number doesn't convey the complex precipitation
picture this spring. The map to the right
shows that western and northern B.C., Yukon, western Nunavut, and most of
Alberta and Saskatchewan experienced drier than normal conditions this
spring. Central B.C., eastern Northwest Territories, Baffin and
Ellesmere Islands, most of Manitoba, southern Ontario, southern Quebec,
northern Quebec and parts of the Maritimes all had wetter than
normal conditions this spring. The wettest spring was 1979 (+28.8%) , and the
driest spring was in 1956 (-21.3%), as shown in
the national precipitation wettest/driest table.
The national
precipitation departures table shows the full list of years in the order
from wettest to driest.
It should be noted that "normal" precipitation in northern
Canada is generally much less than it is in southern Canada, and hence a percent departure
in the north represents much less difference in actual precipitation than the same
percentage in the south. The national precipitation rankings are therefore often skewed by
the northern departures and do not represent rankings for the volume of water falling on
the country.
The
wetter than normal spring, nationally, is in keeping with most of the springs since the
1970's. Only five of the last 31 springs have been below normal, as shown
in the chart to the left. In contrast, the
previous three seasons were drier than normal, as shown
in the consecutive seasons graph. The wetter
than normal conditions around the Great Lakes has helped to raise lake
levels back to near normal.
Continue to the Regional Analysis...
Created :
2002-02-25
Modified :
2003-01-02
Reviewed :
2003-01-02
Url of this page : http://www.msc.ec.gc.ca /ccrm/bulletin/spring02/national_e.cfm
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