Does a woman have to cover her hands in front of non-mahram males?
Question

                With regards to applying henna and hiding the beauty of a woman: How often is it necessary to apply henna and must it be covered in public? Is it necessary or forbidden for women to cover their hands in public, considering what this involves of inconvenience in handling objects with gloves and wearing gloves in hot weather?.
Praise be to Allah.Yes, a woman has to cover 
    her hands, because the hand is part of the ‘awrah. Al-‘Allaamah Ibn 
    al-Qudaamah said in al-Muqni’, as was quoted by al-Mardaawi in 
    al-Insaaf (1/452): The free woman is entirely ‘awrah, even her 
    fingernails and hair. End quote. 
Shaykh al-Islam Ibn 
    Taymiyah (may Allaah have mercy on him) said: It is proven in al-Saheeh 
    that the woman in ihraam is not allowed to wear niqaab and gloves. This is 
    one of the things that indicate that niqaab and gloves were customary among 
    women who were not in ihraam. This implies that they covered their faces and 
    hands. Majmoo’ al-Fataawa (15/371-372). Thus you may know that the 
    woman is enjoined to cover her hands in front of non-mahram men, but it does 
    not mean that she has to cover them with gloves. She may let part of her 
    garment hang down over them, and if she needs to wear gloves sometimes and 
    it is a little hard for her but she can put up with it, then she should put 
    up with it and seek reward for that, because the reward will be commensurate 
    with the degree of hardship involved, as it says in the hadeeth from the 
    Prophet  (peace and blessings of Allaah be upon him). 
And Allaah knows best.