So, my rescue is not spayed, prior owner said they just never got around to it and her heats were never a problem. Which seemed kind of odd to me but not an issue as I can get her spayed. Was more worried she was a puppy mill mom, but they said she never bred and as far as I could tell that seems true. Also then worried a puppy mill might nab her as they were in a hurry to get rid of her for free and seeming to not be be very discriminate, which is also partly why I took her.

Anyways. She went into heat like 1 month after I got her. Halfway through May and somewhat into June. It was very minor. She didn't act different. There wasn't any easily noticeable visual difference. She wouldn't 'present' or anything, she kept her tail down, walked and acted the same for the most part. I almost didn't notice until I noticed a few drops of blood on the floor and then noticed she would mark way more. She was so good at cleaning I rarely saw blood. Wasn't any difference in smell. She was pretty much back to normal by 2.5 weeks.

I suspect this may be why the prior owner wasn't in a hurry to get her spayed. She seems to have very light, hard-to-notice heats.

Anyways that was about 7 months ago. The internet said this is supposed to happen every 6 months, but I see no sign still. Is it possible for a husky to only have a heat once a year? One site said its possible, I'm wondering since she is so light on the heats, maybe she could have only one? Or can the cycle be offset? Like 4 months apart then 8 months apart? Or can they be like 7-8 months apart and each year they happen a month or two later than typical?

My personal experience is with the tibetan mastiff i had growing up was she went into heat once a year. But thats a tm trait. Spider only had it once a year but she is a wolfdog and in that sense follows the wolf side not the sibe side.  Not a big deal but you should get her spayed.

After seeing how minor her heats are it seems like such a serious surgery for what won't be a problem. With my setup in life right now and living situation, I can completely ensure no males will get to her. Maybe if my living situation changed or she was a real nuisance in heat, but it's not an issue right now.

It could be offset and it could also be a silent heat. Silent heats won't present with bleeding which can make them harder to notice. And harder to ensure she doesn't get bred by accident. The main danger of a silent heat is that if you don't know that she is going through a heat cycle you will be less inclined to notice if she develops pyometra, a deadly condition that can follow a heat cycle in an unfixed female. Pyometra is essentially where the uterus and attached parts become infected. If not caught insanely quickly she will die. The possibility of pyometra increases with the age of the dog. If your dog cycled more normally where it was noticeable it would be easier to watch out for her and the risk of it would be much lower, but whereas she does not have a full and clean heat cycle I would be worried that she isn't going to flush her system clean as she needs to during a heat and she may be at a higher than normal for the infection.

is there anyway to discern if its a silent heat?

Not always but there might be subtle behavioral changes. They may start licking more than usual or they may coddle toys more than before. Tenderness in their belly. Could be discharge but might not be colored. Some may become more assertive than normal with other dogs. Other dogs are probably the easier tell since they will often sense the change and be more up in her business. They don't miss heats. They may not fall every 6 months apart but there will be two.

I spayed spider due to mammary tumors at 6 but she was a beast when she was in heat

ok it started... all is good