October is becoming the new Black Friday

• Major retailers are hosting big sales events in the second week of October.
• Anchored by Amazon's Prime Big Deals Days, the period is starting to look like Black Friday.

Astronomically speaking, it's still summer in the US.

Earth doesn't turn towards autumn until the equinox on Sunday, but that's not stopping America's retailers from kicking off the holiday season while the leaves are still green.

Recent announcements from Amazon, Walmart, Target, and Best Buy have the second week of October shaping up to look like Black Friday.

Anchored by Amazon's Prime Big Deals Days on October 8 and 9, the four companies are going head-to-head to win customers' early holiday dollars, turning what would ordinarily be a shorter-than-normal shopping season into one of the longest ever.

Target's event kicks off first, running from October 6 to 12, followed by Walmart from October 8 to 13, with Best Buy and Amazon holding 48-hour blitzes starting October 8.

Besides the fact that retailers are always trying to step up their competition against the might of Amazon at this point — note that all the promotions overlap the shopping giant's Prime Day dates — there are two big reasons behind the shift.

As just alluded to, the holiday shopping season should be shorter this year as Thanksgiving falls late (the fourth Thursday in November), pushing Black Friday all the way out to November 29.

That shaves nearly a week off the period until Christmas, and retailers aren't content to let those big-spending days go.

Of course, the Black Friday dam has been broken for years, with deals starting as soon as Halloween. But what's also pulling things so far forward (shall we call it Green October?) is an increasingly picky shopper.

One of the biggest takeaways during the last earnings season was that customers were still willing to spend — so long as they thought they were getting a good deal. (They also loved to splurge on special occasions.)

After years of high inflation, retailers and the brands they carry are having to compete more vigorously on price to win over consumers. And companies' favorite way of cutting prices is with a bang, not a whimper.

There are certainly more retailers beyond the four noted here who have (or will have) early-October sales events, and the industry peer-pressure plus the good vibes from the Fed's rate cut decision could encourage any holdouts to join the party.

Either way, this year's holiday shopping season is shaping up to be a marathon.