Newcastle, California Weather
Summer solstice light stretched thin. Day 86 of spring. Read this microseason across nine climate regions →
Newcastle weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 13Clear——100°72°—
- SundayJun 14Clear——98°70°-2°
- MondayJun 15Overcast——102°68°+4°
- TuesdayJun 16Overcast——103°68°+1°
- WednesdayJun 17Clear——102°69°-1°
- ThursdayJun 18Mostly Clear——93°63°-9°
- FridayJun 19Partly Cloudy——87°55°-6°
AQI 46 (Good), driven by PM2.5. AQI down 54 over the last 6 hours — air quality is improving sharply. PM2.5 at 9.6 µg/m³, PM10 at 11.9 µg/m³ — typical background levels with no transport signature.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM2.5 at 9.6 µg/m³, PM10 at 11.9 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.81
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
Cut your thistles before St. John, you will have two instead of one.
- Moonrise
- 3:54 AM
- Moonset
- 6:26 PM
- In sign
- ♉︎ Taurus
Summer solstice light stretched thin
Newcastle at a glance
- Today vs. normal: 76°F — typical for the season
- Last frost: April 9 (climatological average for this latitude)
- Microseason: Jun 11–15
- Planting window: Prune spring-blooming shrubs after flowers fade.
15-Day Forecast — Newcastle
- Sat100°73°0%
- Sun98°70°0%
- Mon102°68°0%
- Tue103°68°0%
- Wed102°69°0%
- Thu93°63°1%
- Fri87°55°5%
- Sat88°52°2%
- Sun90°52°0%
- Mon96°56°1%
- Tue103°64°0%
- Wed107°68°0%
- Thu105°68°0%
- Fri106°68°3%
- Sat104°66°0%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 13, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Microseason · June 11–15
Summer solstice light stretched thin
The sun's arc peaks; evening light lingers until past 8:30pm across the coast and Bay Area.
Day 164 of 365 · Wedge 33 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
July is Newcastle's warmest stretch (~76°F) and December its coldest (~46°F); precipitation crests in January at 3.7 inches and ebbs in July to 0.0 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 47° | 3.7″ | 6 |
| February | 50° | 3.5″ | 7 |
| March | 54° | 2.6″ | 6 |
| April | 59° | 1.2″ | 3 |
| May | 66° | 0.6″ | 2 |
| June | 73° | 0.2″ | 1 |
| July | 76° | 0.0″ | 0 |
| August | 75° | 0.1″ | 0 |
| September | 72° | 0.1″ | 0 |
| October | 64° | 0.8″ | 2 |
| November | 53° | 1.8″ | 4 |
| December | 46° | 3.3″ | 7 |
Frequently asked
- When does it freeze in Newcastle?
- Frost typically leaves Newcastle by mid-April and returns to Newcastle near mid-November.
- What is the rainy season in Newcastle?
- January is the wettest month in Newcastle, about 3.7 inches on average; the year totals roughly 18 inches.
- What is the warmest month in Newcastle?
- The warmest stretch in Newcastle comes in July, around 76°F on average.
- What is the coldest month in Newcastle?
- On average December is the chilliest month in Newcastle, about 46°F.
- When can I start a vegetable garden in Newcastle?
- Time tomatoes in Newcastle for two weeks after mid-April; peas and greens start at Newcastle's frost line.
- How many rainy days does Newcastle get?
- Newcastle records around 36 days of measurable precipitation annually.
- What hardiness zone is Newcastle?
- Newcastle sits in the USDA zone set by December lows near 46°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for Newcastle?
- Newcastle's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Newcastle?
- See this week's day-by-day rain chances for Newcastle in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Newcastle?
- Current conditions for Newcastle and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Newcastle forecast updated?
- The Newcastle forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Newcastle?
- Day length in Newcastle peaks around the June solstice — earliest sunrise and latest sunset — and is shortest near the December solstice.
- How accurate is the weather forecast for Newcastle?
- The next few days in Newcastle's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Newcastle, California occupies a hot-summer Mediterranean zone, with January means near 47°F and July around 76°F — a 29°F swing.
Rain and snow bring Newcastle roughly 18 inches a year across approximately 36 measurable-precipitation days.
Latitude 38.9°N gives Newcastle its 29°F swing, and with it the rhythm of Newcastle's growing season.
ZIP codes in Newcastle
- 95658