First you will need to know your latitude and longitude. You can find these at www.heavens-above.com

Once you have your location, you can convert this into your magnetic latitude.

Then, use this chart to find out the intensity level required for your location.

Now you can monitor one of the Space Weather sites to keep track of the current
conditions. My favorites are Spaceweather.com and "Today's Space Weather."

As an example, my magnetic latitude is about 54.6°. I need the Kp
level to be at least above 5 before I'll really start watching the sky.
If you lived in Circle, Alaska, which is at magnetic latitude 71.373°, you
would need a Kp level of 0. This means that they can see them
pretty much all the time if the sky is clear and dark.

Here is a graph that shows the intensity of the Auroras in
the year 2002 at 3-hour intervals. Keeping in mind that I need a 5 or 6 Kp storm
to be visible where I live, you can see how frequently they were out. I also have
these broken down into percentages if you are interested. From these data,
we can see that the Kp index is over 5 for less than 3% of the time.
And 2002 was a pretty good year.