OK, if you want some actual recorded temperatures for the areas you are cycling through, here's the site:

http://www.climate.weatheroffice.ec..../canada_e.html


If you take a look at the Monthly stats for Winnipeg, Manitoba in 2004, for example, you'll see that the extreme minimum temps that year were:

May: -9.8C
June: 2.1C
July: 3C
Aug: 0C

http://www.climate.weatheroffice.ec....Month=5&Day=30

Those kinds of temps usually occur in the early hours of the morning ... often right around dawn ... and it usually takes a few hours to warm up.

So ... for early morning riding, I would recommend taking a few bits of warmer clothing, like a headband, minigloves, tights, light nylon booties, etc.