Newcastle, CA Weather & Growing Conditions

Local forecast, frost dates, hardiness zone and planting guidance for Newcastle, a community in Placer County, California.

Tonight

44°F

Slight Chance Light Rain then Mostly Cloudy

A slight chance of rain before 7pm, then patchy fog between 10pm and midnight. Mostly cloudy, with a low around 44. Northeast wind around 3 mph. Chance of precipitation is 20%. New rainfall amounts less than a tenth of an inch possible.

7-day forecast for Newcastle

When	Temp	Forecast	Wind	Precip
Tonight	44°F	Slight Chance Light Rain then Mostly Cloudy	3 mph NE	19%
Wednesday	66°F	Sunny	2 to 7 mph NW	0%
Wednesday Night	45°F	Partly Cloudy	3 mph NE	0%
Thursday	68°F	Sunny	5 mph N	0%
Thursday Night	45°F	Clear	3 mph N	0%
Friday	70°F	Sunny	3 mph W	0%
Friday Night	48°F	Clear	3 mph E	0%
Saturday	73°F	Sunny	3 mph NNW	0%
Saturday Night	50°F	Mostly Clear	3 mph N	0%
Sunday	73°F	Mostly Sunny	5 mph W	0%
Sunday Night	51°F	Partly Cloudy	3 mph N	0%
Monday	71°F	Partly Sunny	3 mph SSE	2%
Monday Night	50°F	Partly Cloudy	2 mph ESE	2%
Tuesday	71°F	Sunny	3 mph SSW	7%

Forecast source: National Weather Service (api.weather.gov) for Newcastle (38.867, -121.132). Updated through the day.

Growing snapshot for Newcastle

Last spring frost

Feb 25

First fall frost

Dec 5

Growing season

286 days

Hardiness zone

More local growing data for Newcastle: nearby ZIP 95658 weather · frost dates · planting calendar · California frost dates

Nearby towns & communities

Alta Auburn Carnelian Bay Cedar Flat Colfax Dollar Point Dutch Flat Foresthill Granite Bay Kings Beach Kingvale Lake of the Pines Lincoln Loomis Meadow Vista North Auburn Penryn Rocklin Roseville Sheridan Soda Springs Sunnyside-Tahoe City Tahoe Vista

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Climate data from the nearest NOAA station, Auburn, Ca (4.9 mi from Newcastle). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.