When Blue, Steve, Mr. Salt, and Mrs. Pepper are looking at snowflakes through the window in the kitchen, they would not be able to see the snowflake patterns in real life, nor would any snowflakes look alike in real life.
At the start of the episode, it looks like a beautiful, summer day outside and there are leaves on the tree. In real life, there would be no leaves on the tree and it would be cloudy, although the sun does shine when snow is on the ground.
When Steve is about to draw the third clue (a snowball), just as he was getting his notebook and while he was turning the first two pages in his notebook, if you look closely, you can see that there is literally nothing on those two pages.
After Steve draws the third clue (a snowball), the pawprint is still seen on one of the big snowballs.
When Blue skidoos into the calendar, Steve's skidoo sound plays. This is the only time in the series this has happened.