Consider playing a bit more cautiously around Kennen when you have a Mark of the Storm debuff. If he hits you with 3 Marks of the Storm, you will get stunned.
Kennen is flimsy by nature - turn and attack him if he gets careless with Lightning Rush.
The stats provided here highlight several significant Yuumi vs. Kennen counter statistics that can help us realize the differences and similarities between the pair. Yuumi’s KDA ratio ([kills + assists] / deaths) of NaN is more than Kennen’s KDA ratio of NaN, highlighting that Yuumi may be more central to her team's team fighting potential than Kennen. This observation is largely caused by the differences in assists.
Yuumi usually has a significantly smaller longest kill spree than her opponent does. On average, she takes less damage than Kennen. This commonly reflects differing health capacities; however, it can also imply that the one champ has less agility and thus is not able to flee from further damage when engaged or poked.
Both LoL champs are great champions. Both have their strengths, weaknesses, and counters. In League's current meta, Yuumi usually loses when trying to fight Kennen, with a 43.9% win rate. Thus, Yuumi makes a poor counter for Kennen.
While Yuumi does have a much lower winrate than Kennen, when they face off with one another, Yuumi also has a lower difficulty level that makes her a less difficult champ to develop with. You should be very concerned when picking Yuumi into Kennen.
Furthermore, Yuumi has a great amount of CC and other utility, a similar amount to Kennen. This makes her just as valuable during team fights, especially when facing champions with a lot of burst damage.
While there isn't a single best champion overall in League of Legends, in Yuumi vs Kennen matchups, Kennen is the better champ with a much lower win rate, less champion complexity, and a similar amount of utility to help out your team members during late stage team fights.
Yuumi is a terribly counter for Kennen. You will do well by focussing your play on maximizing your gold income and clearing objectives. If you do that, you should do very well as Yuumi against Kennen.
If you would like to truly master Yuumi in order to counter Kennen during both the lane and mid / late game phases of League of Legends, you should keep reading to pick up a few extra tips and tricks for this matchup. If you mind the build and suggestions shown above, you should increase your win rate significantly and be that much closer to League of Legends pro players.
Yuumi typically picks up a lot less CS relative to Kennen. Champs who typically don't take much CS often don't need much CS to be valuable teammates, such as sup champs. These kinds of champions are able to scale properly off of their abilities and first items alone. Yet, champions with a lot of CS, such as hyper-carries, usually need many items to be effective. In either situation, try to surpass the values reported here to do well.
The most important items to use in your Yuumi versus Kennen build include Mikael's Blessing, Ardent Censer, and Moonstone Renewer. When Yuumi incorporated at least these three items in her build, she did a lot better vs Kennen than with most other typical builds. In fact, Yuumi boasted an average winrate of 43.9% battling Kennen with these items in her kit.
To have the greatest probability of coming out on top against Kennen as Yuumi, you should equip the Summon Aery, Manaflow Band, Transcendence, Scorch, Font of Life, and Revitalize runes from the Sorcery and Resolve rune sets. Of all the runes players picked for Yuumi vs Kennen counter picks, this set of runes resulted in the best win rate. Notably, these runes averaged a 43.9% win rate overall.
If you want to get Yuumi x Kennen tips and counter stats for a a specific skill level, feel free to select one from the selection menu provided above. By default, the statistics and build suggestions shown are computed using every match played with both champs.