Hunting success chances fluctuating despite high-stat wolves and 100% synergy/proficiency

So I got all of my wolves in my party up to 100% proficiency and I got the synergy up to 100% as well. The success percentages I had on the hunts were really great: 100% for critter and small trails, over 70% for medium trails, and over 50% for large trails. 

Now all of a sudden, those percentages have dropped dramatically?? Despite no change in the synergy or proficiency levels. What's up with that? Is it because of the season change? I would think the success rate would go up in the warmer months, like they do in real life. 

iirc spring and .. autumn? are considered the easiest months. hence why it changes in summer, and winter, with winter being the hardest

Oooh, that lines up with what happened to my last hunting party. They had the same high percentage success during fall but suddenly it just tanked during winter.

Thank you! I didn't know they actually had that as a feature.