Planning 2021 archery elk using the equinox and moon phases

Chris Neville with OTC archery bull elk

Chris Neville with his 2020 archery elk. Photo credit: Sam Sarbacher

When it comes to planning your 2021 archery elk hunt, there are so many unforeseeable factors involved; however, a lot of hunters center their planning talks around the moon phase and the fall equinox, which is when the rut really starts to turn up and the peak breeding is underway. From my experience, I can honestly say that I am a firm believer that hunting anytime during the month of September can prove to be the best day or week — no matter if it's the first week or last week of the season. Of course, this can change from one year to the next and there are pros and cons of each week in September. Here, I have broken this down for this September so you can analyze the moon phase and fall equinox to plan your perfect hunt and request the right days off of work.

What is the fall equinox?

The fall equinox is one of the times of the year when the sun rises due east and sets due west, specifically on the equator. The daylight hours and evening hours should be relatively equal, which provides long days and lots of hunting time. The daylight hours have been getting shorter since the summer solstice, but now that the sun is spending more time south of the border, the shortening of days speeds up. The fall equinox is also the official start of the season of fall. You may be thinking that is great information, but what does that have to do with archery elk hunting and how does it benefit you? 

Why the fall equinox is important

The reason the fall equinox is so important to elk hunters has to do with cows coming into estrus and being ready to breed. According to most experts and biologists, cow elk start to enter their first estrous cycle right around the fall equinox, usually within five to ten days of this specific day. Since most cows will be ready to breed, bulls will tend to be very vocal in an attempt to attract more cows into their harem. This is beneficial when trying to locate a herd bull and can provide some very good hunting opportunities if you are in the mountains. A lot of hunters use the fall equinox to plan which days they want to be in the mountains year after year. This year, the fall equinox is occurring on Sept. 22; however, it is typically either Sept. 22 or 23 every year so you can consistently plan your days off in advance. Since we know when most cows come into estrus, we can also understand that these are the prime breeding days of the elk rut. If you look five days before this and five days after to plan your hunt, you will be hunting Sept. 17 to 27. This ten-day stretch should prove to have the most breeding action; however, there is one problem hunters will face in 2021 and that is the moon phase!

Moon phases and how they affect your hunt

Moon phases on unit profiles

Remember that you can check out moon phases on every Unit Profile on INSIDER.

If you remember 2020, the new moon was on Sept. 17, creating dark nights and active bulls activity late into the morning. This year, in 2021, the new moon is on Sept. 7 and the full moon is right smack dab in the middle of the prime breeding days on Sept. 20. This could negatively affect the daylight activity of elk since a lot of hunters, including myself, seem to see an increased amount of nighttime feeding and breeding activity under a full moon and decreased amount of daylight feeding and breeding through the weather, temperature, number of cows in estrus and hunting pressure will all play a role in this, too. Consequently, this might lead you to think that hunting sometime between the new moon and full moon instead of the peak breeding day may be an effective strategy this year to avoid the bright nights of the full moon.


This year is not a slam dunk for hunting both the prime rut days and new moon phases like 2020 was; however, there are some conclusions that can be made. Overall, though the prime rut days may be Sept. 17 to 27, a hunter who wishes to hunt both the equinox and moon phase may choose to shift up their hunt a few days and concentrate on Sept. 10 to 20 or even a few days further and hunt Sept. 5 to 15. Though the cows may just start to come into estrus by the end of these hunt dates, bulls will still be engaged in rut activity and establishing dominance. This fight for dominance seems to make them more susceptible to get fired up during a bugling sequence. If you have a chance to hunt the later days of September into early October with a bow or rifle, you may see an increase in daylight elk activity as early as Sept. 26 to 28 as the moon continues to wane. No matter when you hunt in 2021, you can and should expect to have good days and bad days of elk activity based upon an unforeseeable number of factors; however, no time chasing elk is really a bad day.

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