This WVDNR page makes it sound like only a once a year thing. Is that true? I know they spawn several times a year down south but I thought they'd regularly get off at least two up here.

Spawning frequency 'it all depends'. Mostly on length of growing season. The longer the growing season the more likely multiple spawns will occur. Another factor is age of the fish and when it matures. Late spawned fish can mature later in the year and spawn later in the year, thus it may appear multiple spawns.

My opinion here..
I think there are not only age differences that affect spawning timing but other triggers that we may never know 100% for sure.
I would say I disagree with the general thought that a "colony" moves in and spawns all at the same time. I think the window is quite large compared to other species such as bass, walleye etc..
I've seen BG on nests in May and still seen males guarding nests in August.
Not sure that females produce more than 1 time a year but I do believe it's mother nature providing young of year to hit the best survival conditions come hell or high water.
There may be a period where water temp is such they slow down or pull out (sounds bad) but they may resume to some extent after temps cool down slightly.

There you go, two good answers for timing of bluegill spawning in central latitude and northern US. Spawning can occur in the temperature range of 69F-89F; with probably the main spawn period occurring when the water reaches 70-75F in spring.

Thanks everyone. Just knowing there isn't a set series of "bluegill spawning seasons" helps.

Like everything else, it all depends. An extended warm Autumn can allow spawning at a later date.

...can you imagine catching a bluegill (with attitude) over 31" like this article says! On your ultra-lite! Haha

Agree Dave - I regularly get Fall hatches of gills in Ohio.

I also question the statement of all spawning within hours

Temp and photoperiod control well conditioned fish spawning. There is no set in stone answer to how many times , when or how long the events take. Altitude can effect temp and photoperiod. If a pond is on the west side of a mountain slope it can effect photoperiod (morning sun reduced). It also effects water temps.

I'm in central Virginia and I was seeing bluegill fry in early november so I assume at least some were spawning in Oct.

That is not an unusual occurrence especially if there is a warm fall period.

I have my own thoughts on the Bluegill spawn. My belief is that each fish will only spawn once a year in the northern part of the US, possibly 2x year in the deep South. BUT I don't believe that ALL Bluegills in a body of water will spawn at the same time unless there is enough suitable spawning areas for them to do so. I believe that the most dominant fish spawn first, then next month the less dominant fish that didn't get a spawning area the previous month will spawn.

Think about the numbers of the bluegills in a particular BOW. Given that they spawn in a relatively narrow area in a pond (roughly 1'-5' depth depending on water clarity, water depth and substrate) and that each male makes a nest anywhere from 12" to 24" diameter, there may not be enough area for all the bluegill to spawn that month.

I feel that bluegills will spawn any time of the year when the water temperature is consistently above 72°F, and they typically spawn here right before or during a full moon.

I believe in Texas Bluegills have been observed spawning as late as November and as early as February, if the water temperature is warm enough.

I haven't seen a Northern Bluegill (talking North of central Indiana) have carrying eggs or milt past the full moon in August. I have seen them spawn as early as the full moon in May.

Scott, it is my personal, untested, etc belief that our long warm water periods contribute to last years late hatched ones, and some that might get hatched early getting big enough to spawn later.

But, I se more nests in the Spring than later

For good insight on BG nesting look for a series of studies by Neff.