Regarding California in 2100 AD and specificaly Sacramento

 

Extreme Heat Waves: Cities like Sacramento will experience a "Phoenix-like" climate, with the number of days topping 104°F skyrocketing from an historical average of 4 days a year to around 40 days a year. 

🌧️ Precipitation: The "Weather Pendulum"

Total annual rainfall averages may not change drastically, but the way it falls will be highly volatile: 

Precipitation Volatility: Researchers at UCLA project a 100% to 200% increase in the frequency of extremely wet winter seasons driven by hyper-intense atmospheric rivers. Concurrently, the frequency of extremely dry years is expected to surge by 50% to 150%. 
Vanishing Snowpack: Higher temperatures mean winter precipitation will fall as rain rather than snow. The Sierra Nevada snowpack is projected to decline by two-thirds, fundamentally straining California’s water storage system.