A patio should slope 1/8" to 1/4" per linear foot away from the house. A 10' patio should slope at least 1.25" to 2.5" away from the house.
Since you have already poured the patio, it good future information.
I would recommend you get in the habit of shoveling your new patio to reduce the effects of standing water/ice that will occur. The thawing/refreezing cycle will not be helpful to the new patio. What is done is done.
As glennjanie writes, it is best to have the patio below the siding since you do not want rainwater backing up to your house and spilling over the top of the foundation or sill plate of your home's framing. Again, what is done is done.
In some cases, the general grading of a lot will force your hand about what you can do. Perhaps this was your case. Anyway, you will need to be attentive to rain/snow issues and try to minimize the effects.