May has been frigid slowing the planting and emergence of the summer crops in Canada. Late freezes and even snows are still occurring regularly and can be expected the rest of the month.
Canada May 2009 temperature anomaly
© NOAACanada May 2009 temperature anomaly

The chart above shows the May 2009 temperature anomaly through May 24th. Parts of central Canada (Churchill, Manitoba) are running 16 degrees F below normal for the month through the 26th (map ends 24th). Every day this month has seen lows below freezing in Churchill and only 6 out of the first 26 days days had highs edge above freezing. The forecast the rest of the month is for more cold with even some snow today in Churchill and again this weekend perhaps further south.

Hudson Bay remains mostly frozen though most of the seasonal melting occurs in June and July most years.

Parts of the south central region were also cold in April averaging 3-5 F below normal. The winter (December to March) was a cold one for southwest and central Canada but warmer in the far northeast.
Canada Dec)8 Mar09 temperature anomaly

Meanwhile the arctic ice remains higher this data for any year this decade in a virtual tie with 2004.
Northern Hemisphere Sea Ice Anomaly
© unknown

Given the polar stratospheric aerosols from Mt Redoubt, and a colder Atlantic and a continued cold Pacific, the recovery from the minimum of 2007 should continue this season.

The global data bases have large gaps in Canada, Africa, South America. So they will not reflect this in their global May anomalies as well as the satellites that see the entire surface - land and ocean excluding high latitude polar.

See pdf here.