Great work! What do you think is causing such a great spring? Good public water?
I'll give you a more complete answer. Pigs are polyestrous. Meaning they are capable of cycling into heat continuously. But keep in mind that just because they are capable, does not mean they will. Their environmental conditions need to be favorable for supporting babies, in addition to their own life. Humans are also polyestrous, but hard core female athletes stop cycling (their peroid stops) due to the bodies perception of a poor environment (meaning all food was being utilized to sustain the body, with nothing left over to support life in the womb).
So typically during summer, in southern Ca, food supplies are not prolific, so cycling typically shuts down in the pig population. Obviously crops can change that. But not all pigs are near crops. As winter approaches, we typically have a resurgence of food, acorns is but one example. (Our deer need these foods for reproductive and survival purposes, and pigs are a major competitor impacting our deer herd numbers). Freezing weather, especially prolonged freezing significantly degrades the quality of avaliable leafy feed for pigs, and typically we have rain, thus rooting increases, as the soft ground requires less energy expenditure. Keep in mind, for any animal to survive, they must take in more energy than they expend.
So, the greatest times of pig activity is in spring, when sows are pretty much guaranteed to be in estrus (heat), and the boars will be on the hunt (traveling) for receptive sows. So your chances of seeing a pig, or pigs is higher during this time of year, especially on cool days. However, if you hunt an area with acorns, the pigs will be hitting the acorns hard, and this is also a time of high pig activity that increases the odds of seeing pigs. In spring, your odds are higher of seeing lone boars. When acorns are on the ground, your odds are high for seeing founders, drifts or droves (referring to groups of pigs).
With that said, if you hunt pigs in the summer, keep in mind that pigs do not have sweat glands, so they don't sweat, like dogs. But they have to regulate their body temperature to survive. So the will dig out dirt spots in the shade to lay in, and or enter the water. So in summer, you might want to concentrate on water sources, creaks, springs and ponds they can lay in. They will literally enter ponds and hang in the water. I've sat and waited for one or more to exit the water, as I did not want to take a swim to retrieve them. Keep in mind that rattlesnakes often hang around water sources. But, if you're hunting public land in non-refridgerator temperatures, you have limited time to get the meat on ice.
Lastly, sows do not have armor (super hard fat type tissue), so sows are sooooooo much easier to skin, quarter and debone than boars. The boar in the Pic of this post, or when you look at the picture, you see what at first looks like white/Grey hair. It's not hair, it is scaring. Tons of scaring from head to buttocks. The fat under all that scaring hardens, simular to their armor shield in the shoulders. So this particular pig was a pain to skin, and took an excessive amount of time.