Up to 90 days of daily highs, lows, and precipitation chances. Today’s and tonight’s Cupertino, CA weather forecast, weather conditions and Doppler radar from The Weather Channel and Weather.com Outdoor activities may be pursued comfortably on most days of the year. 4-Day Weather Forecast For Cupertino. Local news and events from Cupertino, CA Patch. Report Station. Patchy Fog then Mostly Sunny in the day; while Mostly Cloudy then Slight Chance Light Rain during night. CUPERTINO, CA(Updated at 8am ET)Here's your weather forecast for the next 4 days. CUPERTINO, CA(Updated at 8am ET)Here's your weather … Maximum temperature yesterday: 68 °F (at 1:53 pm) Minimum temperature yesterday: 42 °F (at 3:53 am) Average temperature yesterday: 52 °F. Know what's coming with AccuWeather's extended daily forecasts for Cupertino, CA.