Another GLP Solar Mystery Solved! Someone please pass this on to BendingTheLight and the others....

Sorry I forgot about this old NASA News story from 2008 (PR for THEMIS Mission) until I saw Spaceweather.com linked to it the other day. This explains why the magnetosphere is extra jumpy around this time of year.....

SPRING IS AURORA SEASON-

It turns out that rope-like magnetic connections between Sun and Earth are favored in springtime. It's a matter of geometry: As Earth goes around in its orbit, Earth's tilted magnetic poles make different angles with respect to the Sun, tipping back and forth with a one-year cadence. Around the time of the equinox, Earth's magnetic field is best oriented for "connecting-up" with the Sun.
But wait, there are two equinoxes, spring and fall, with similar magnetic geometry. Indeed, studies show that fall is aurora season, too. Geomagnetic disturbances are almost twice as likely in spring and fall vs. winter and summer, according to 75 years of historical records analyzed by solar physicist David Hathaway of the Marshall Space Flight Center: diagram.
So, 'tis the season for auroras--and lots of data for THEMIS. Says Sibeck, "we welcome the spring!"

[link to science.nasa.gov]

Yes, indeed, happy Spring to all.

Finally a story about planetary alignments which makes sense to me,LOL.