When is the best time for growing beets?
When Is the Best Time for Growing Beets
Certified GKH Gardening Expert
Beets normally prefer to be grown a bit on the cool side; therefore, it is better to grow them during the coolest part of spring and fall. This article should help: https://www.gardeningknowhow.com/edible/vegetables/beets/growing-beets.htm
As long as the "normal" weather is kind in your area of the world you can grow beets pretty much most of the year.
I have grown beets (in successive weeks) from March to October here in the UK and have had very good results. But (there is always a but) it depends on the variety you want to grow, your soil type and as I said the "normal" weather in your area.
Hope this helps