Swix's PS series is great for both training and competition. They are versatile waxes that have low melting points and are easy to apply.
Blue 6: 21 F - 10 F (-6 C to -12 C).
Red 8: 34 F - 25 F (+1 C to -4 C).
Yellow 10: 50 F - 32 F (+10 C to 0 C).