I suppose KIE gave the most reasonable answer. So yeah, a mountain even taller than Everest and situated smack dab on the Equator would still have a snowcap, as strange as it would seem. (There are a few African mountains that do have snow and ice at the summit.) The atmosphere simply becomes too thin to conserve the solar energy, and the sunlight by itself can't melt ice effectively enough - otherwise we'd have a thaw every time the sun came out during winter. And if the sunlight would be strong enough, it'd be too intense for any life to survive above ground.
On another note, that's an amazing drawing you've got there! Technically speaking, this is almost a masterpiece. There are barely any contours, all the various shapes are defined through their shading and highlights. The colour range is surreptiously complex; you've blended a great many different colours yet it looks almost monochromatic. The scenery is awash with the strong dual theme of red and blue, but the clothes of the two humans catch the light naturally, the actual colours of the fabrics showing through. The poetic feel is wonderful; it's like a midsummer night, sun and moon meeting in the sky above as the couple meets on the earth beneath. Two mortal beings caught in a moment of pure magic.
Needless to say, I really like it. I'm rather intrigued by the fact that the woman is on the sun's side and the man is on the moon's side; it's usually the other way around. Dare I ask how long it took to make?
/Tuan