Last night was a bust for auroras, at least, for most. It didn't even seem like a timing issue, as the Kp index (a measure of the level of disturbance in earth's magnetic field) didn't really move much. That being said, the Kp index is derived from a weird mix of science and witchcraft over a 3 hour window and gives a standard quasi-logarithmic number that's valid for all latitudes which is reported after the 3 hours intervals at specific times ie 0000 hrs, 0300 hrs, 0600 hrs, 0900 hrs...1800 hrs, 2100 hrs. Anyway, fingers crossed for the rest of the weekend and here is the Kp forecast courtesy of NOAA.
NOAA Kp index forecast 04 Oct - 06 Oct
[edited out the scheduled times... since my reposting it.. screwed up the format... must be some kind of magic contained therein]
NB Time is universal - remember to convert for your locale. Should be good tonight in Europe and North America.
I thought that auroras were more of a thing in the summer time in the northern hemisphere and in the winter time in the southern hemisphere.. .. although probably the southern hemisphere would be calling our wintertimes to be their summer times... if you know what I am saying?
So maybe then I might assert that I thought that auroras were more of a summertime thing.. ..
Yeah, the middle of the planet is always summer, but they don't get auroras... another weird contradiction. Go figure.
I should preface this explanation with the following disclaimer: I am not a pharmacist. That being said...
The auroras can occur at any time of year and generally in the north and south simultaneously though not symmetrically (not a mirror image) but they get a probability boost right around the equinoxes. This is theorized to be due to the fact that the magnetic poles are at right angles to the flow of the solar wind 2 times per day due to the tilt of the earth's rotational axis. The auroras also get a probability boost from increased solar activity which seems to follow an 11 year cycle as the sun's magnetic poles flip. The middle of that cycle is the maximum activity which is about where we are now. This solar activity results in flares of varying sizes and coronal mass ejections which alter the prevailing solar winds and cause disturbances in our magnetic field. Larger disturbances will manifest at lower latitudes. You have to consider the length of day as well though; shorter days means more time to potentially view auroras since they don't always occur after sunset. Daylight sun totally ruins the view.
Right now, in the fall (near the equinox) with near-maximum solar activity, especially considering the sun just showed us a X9.1 flare - there is a really good chance to see the aurora but the problem is the sun doesn't always flare in the best direction to shower us in plasma... sometimes that's a good thing because we really don't want another Carrington event (although it would come with the best auroras ever) because that would likely plunge us into darkness for a long time... ain't nobody got time fo' dat.
TL;DR
auroras - any time of year - more likely during the equinox.