For a country that's half desert, Botswana has a surprisingly agreeable climate. Sunshine is ample year round, from the driest reaches of the south to the wildlife-studded swamps of the Okavango Delta. The stretch from the Delta to Francistown is the wettest part of the country, but even during the wet season (October–March) thunderstorms arrive only about every fourth day on average, and they seldom last long; in fact, drought is a recurring problem. Humidity is high but not insufferable in and near the Delta, where fog softens some winter mornings. Conditions are much drier to the south. The mostly rainless winter months see temperatures dip below 10°C/50°F at night throughout Botswana. Light freezes can occur, but the bright afternoons often top 21°C/70°F. Although the relatively small scope of the Kalahari limits the extent of dust storms, winter squalls can whip across the pans of the northeast and bring a stinging round of windblown salt and dust.