Melee allies can stack Frost for your Permafrost, keep an eye on who they are attacking.
Save Glacial Prison for encounters where you have teammates present to take advantage of it.
Use Arctic Assault to escape bad situations, interupt channeled spells or chase runners.
Try to engage him in short bursts instead of going toe-to-toe with him. Preventing him from attacking consecutively drastically lowers his damage output.
Jax can dodge all incoming attacks for a very short amount of time and stuns enemies in melee range when it ends. Wait to strike him until after his dodge is finished.
The stats shown on this page highlight several critical Sejuani versus Jax matchup stats that may help us interpret the differences and similarities between this set of champions. For instance, Sejuani’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Jax’s KDA ratio of NaN, showing that Sejuani may be more central to her team's team fighting capability than Jax. This observation is largely a result of the differences in assists.
Sejuani typically has a slightly smaller longest kill spree than her enemy does. Typically, she takes more damage than Jax. This typically indicates differing health capacities, yet it can also imply that the one champ has less mobility and thus is not able to kite away from additional harm when engaged or poked.
Both League champs are great champions. Both champs have their strengths, weaknesses, and counters. In League's current meta, Sejuani usually loses when taking on Jax, with a 44.7% win rate. Thus, Sejuani makes a bad counter for Jax.
While Sejuani does have a much lower winrate compared to Jax, when facing one another, Sejuani also has a lower level of difficulty that makes her a less time consuming champ to learn and master. You may get destroyed when picking Sejuani into Jax.
Moreover, Sejuani has a good amount of utility and CC, a similar amount to Jax. This often makes her just as valuable during teamfights, especially when trying to counter champions with a lot of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Sejuani vs Jax matchups, Jax is the better champion 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.
Sejuani is a bad counter to Jax. Focus your gameplay on keeping up your gold income and taking out objectives. If you are able to do that, you should hold your own as Sejuani against Jax.
To truly master Sejuani to counter Jax during both the laning and mid / late game phases of League of Legends, you should continue reading to pick up a few extra tricks and insights into this matchup. If you listen to the build and stats displayed here, you should grow your win rate significantly and be closer to League of Legends pro players.
Sejuani typically accumulates less CS compared to Jax. Champions who typically don't take many minion kills often don't need much CS to be effective, such as support champions. They are capable of scaling properly off of their abilities and first items alone. Yet, champions with a lot of CS, such as hyper-carries, often require many items to be effective. In either case, try to surpass the numbers reported here to do well.
The most crucial items to prioritize in your Sejuani versus Jax build include Thornmail, Hollow Radiance, and Jak'Sho, The Protean. When Sejuani bought at least these three pieces in her build, she performed significantly better when fighting Jax than with most other typical builds. In fact, Sejuani had an average win rate of 44.7% battling Jax with this counter build.
To have the best chance of annihilating Jax as Sejuani, you should take the Aftershock, Font of Life, Conditioning, Overgrowth, Legend: Alacrity, and Triumph runes from the Resolve and Precision rune sets. Out of all the rune combinations players picked for Sejuani vs Jax fights, this composite of runes yielded the greatest win rate. Moreover, these runes provided a 44.7% winrate overall.
By default, tips, statistics, and builds on how to beat Jax as Sejuani are displayed for all ranked divisions. If you would like to narrow the stats and builds to a particular skill level, you may use the selection menu located earlier in the counter matchup guide.