Slow release fertilizers (if they are not completely organic) are slow release because the beads (or pieces) of fertilizer have varying thicknesses of a coating that breaks down in time, due to microorganisms or natural physical breakdown. Inside this coating, then, is the fertilizer that is "slowly" released. Actually, once the coating integrity is breached, the fertilizer is quickly released, but due to the multitude of beads that are breached at different time intervals, the overall action is slow release. People claim that they find broken insect eggs in houseplant soil frequently, but in actuality, it is these beads that have cracked, the fertilizer released, and the rest of the shell (the coating that is resistant to breakdown) remains.
It's true that slow release fertilizers release faster in hot weather. All chemical reactions work faster with warmer temps. But it's a silly notion that things don't break down in, say, 50F weather. A slow release fertilizer that claims 3 months of feeding might feed (at a much lower rate) for 6 or 9 months for you. Bonemeal is slower release than any processed slow release fertilizer. Liquid fertilizers are fast acting, but would be slower in your case for the same reason.
