The sun has a heartbeat. Every 10 or 12 years it beats, and it beats hard. This is known as the solar cycle and is measured by the number of sunspots visible on the sun. The more sunspots, the more solar flare energy is being released into space which means more aurora activity!
Q: Where are we now on the solar cycle?
A: We are in the second half of the peak phase but it is predicted that sunspot activity will start diminishing in the next 1-to-3 years. Years 2015 & 2016 still hold great potential for some big solar flares. I remember from the last solar cycle peak in 2000-2001 that some of the wildest displays occurred after solar max.
Q: When is the best time to see the northern lights?
A: Between 11pm and 2am are the peak aurora hours but they can show up anytime from dusk until dawn. Some of the most colorful displays I've ever seen occurred in dawn's early twilight around 5am-7am.
Q: When should I plan my aurora hunt?
Statistically, the equinox months of September and March are the best for aurora activity but the winter months of October-thru-February are also good. In northern latitudes like Fairbanks, Alaska the summer months of May, June & July are too bright to see the aurora. It's challenging to pinpoint the exact timing of a big display. The best advice I can give is to be patient, diligent and pay close attention to the websites that monitor space weather then go for it when the timing seems right. Luck favors the prepared.
Historical Solar Cycle
SIDC-team, World Data Center for the Sunspot Index, Royal Observatory of Belgium,
Monthly Report on the International Sunspot Number,
online catalogue of the sunspot index: http://www.sidc.be/sunspot-data/, ‘1750-2011’