Halo effect... in summer!

Today took a small bicycle ride around the city. At one moment looked up to the sky (wanted to check amount of clouds) and... this is rare natural phenomenon - sun halo effect. Wikipedia says, that it's "an optical phenomenon produced by ice crystals creating colored or white arcs and spots in the sky". However, currently is hot weather, there shouldn't be ice crystals in atmosphere or am I wrong? Anyway, this is first time I saw such phenomenon, and even get a bit dazzled while looking at it and taking these pics.