The best time to visit is mid April through October when days are warm or hot. July and August in Baku can bring daytime highs of up to 100 F/38 C. Evenings tend to be cool, even in the summer. Don't go from December to late February, when inland temperatures can be bitterly cold -- even in Baku, it can reach below the freezing point. The climate varies considerably from east to west -- in the western mountains, the weather is drier and more extreme. The eastern part of Azerbaijan, near the Caspian Sea, has a more moderate climate. No matter when you go, be sure to take a sweater for the cool evenings.