How to counter Varus
Let us take a look on how to beat Varus. We will look at champions who are strong against Varus and who are weak against Varus. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Adc champion who counters Varus. You can already win in champion select with the right counters for Varus. If you want to know how to counter Varus then you need to take into account the best picks vs Varus and the worst picks vs Varus. This Varus counter data is based on matches played by Pros on patch 13.24 and previous ones. It is important to see whether Pros counter picked Varus or whether they played as Varus.
Champions used by Pros to counter pick Varus
Looking at the matches from Pros (see table Pros counter picked Varus) we can see that they picked 
Kalista most often to counter pick Varus. The matchup Kalista vs Varus occured 115 times. Varus has 53 wins and 62 losses in this matchup. Learn how to counter pick Kalista to get another perspective on the data.
Lane outcome for Varus
When looking at Varus counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Varus. The lane outcome of Varus consists of three outcomes: Win, Loss or Draw. Let's take a look of Varus lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Varus.
Conclusion
Analyze the available data and learn how to beat Varus. To master Varus take also a look on Varus builds and runes for Varus. Good luck, Summoner!