Stanford University's climate is mild. Average winter daytime temperatures is in the 50's Fahrenheit (15 Celsius) and in the summer highs in the 70's Fahrenheit (about 25 Celsius). The temperature does tend to plunge after sunset. Rain only falls from about October through April and it last snowed here in 1976. Humidity is usually low. Check out the current weather forcasts for Palo Alto and San Francisco (note that San Francisco is usually cooler than Stanford University).