Death Valley is among the hottest areas on the planet. You can expect temperatures as high as 49 degrees Celsius (120 degrees Fahrenheit), and these are common between June and September. Between November and March, the weather is mild, and this is where you can expect temperatures of around 15-25 degrees Celsius (60-70 degrees Fahrenheit). Death Valley hardly sees rain, but that which falls in the mountain sends flood down canyons.
The weather is at its best from December to January. During summer, Death Valley is scorching, so travel only when the weather is not too hot.