Thanks Julia for your question.

I have some good and bad news about the weather for April 1st (April fools day) and April 2nd.  I'll start off with the bad.  You might want to bring your umbrella and rubber boots for Wednesday, at least for the morning and early afternoon.  There is a system currently moving from the Pacific Ocean, which will move into southern Ontario Tuesday night.  This system will bring 10 to 15 mm of rain to the GTA before slowly clearing east Wednesday evening.  Inside activities may be a good idea if you don't want to get wet. 

Now for the good news; Thursday will feature dry weather with temperatures near 10 degrees.  There should be sunny breaks throughout the day as a weak ridge of high pressure moves in from the east.  Winds should be fairly light making for some decent conditions to be outside.

Remember the right gear and try to have a good time on your trip, if anything changes I'll let you know.

Chris