Daily Halacha - Summer Laws, 8th of Sivan 5777

Is it permissible for a prayer leader to pray wearing a short-sleeved shirt?

A prayer leader who wears a shirt with very short sleeves to the extent that part of the arm between the elbow and shoulder is exposed should not, ideally, lead prayers in this manner out of respect for the congregation. Instead, he should wrap himself in a tallit and cover his arms. This is also in keeping with the principle "Prepare to meet your Hashem, Israel." However, if the entire upper arm to the elbow is covered, he is permitted to lead the prayers even initially to fulfill the congregation's obligation. If there is no tallit available to cover his arms, in cases of necessity, one may be lenient and allow him to serve as prayer leader even while wearing a short-sleeved shirt.

In any case, one should be careful not to cause disputes over this matter. A person wearing short pants with exposed thighs and calves is not permitted to lead prayers until he dresses appropriately [Yalkut Yosef Siman 53].

Ach Tov V'Chesed - Daily Halacha