Newcastle, Washington Weather
Fireweed Ignites. Day 14 of summer. Read this microseason across nine climate regions →
Newcastle weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Overcast——71°57°—
- SundayJul 5Overcast——73°52°+2°
- MondayJul 6Overcast——82°50°+9°
- TuesdayJul 7Overcast——82°52°0°
- WednesdayJul 8Light Drizzle15%0.02″65°57°-17°
- ThursdayJul 9Overcast13%—77°52°+12°
- FridayJul 10Clear——83°48°+6°
AQI 38 (Good), driven by PM2.5. AQI up 6 over the last 6 hours (gradual rise). PM2.5 at 8.8 µg/m³ (AQI 49) with a 0.77 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
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 8.8 µg/m³ (AQI 49) with a 0.77 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.77
- Wind
- calm
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:17 PM
- Moonset
- 10:11 AM
- In sign
- ♓︎ Pisces
Fireweed Ignites
Newcastle at a glance
- Today vs. normal: 7°F below the seasonal normal for this latitude
- Last frost: May 31 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — Newcastle
- Sat71°57°2%
- Sun73°52°0%
- Mon82°50°0%
- Tue82°52°1%
- Wed65°57°15%
- Thu77°52°13%
- Fri83°48°4%
- Sat81°53°11%
- Sun74°50°6%
- Mon72°48°6%
- Tue82°46°5%
- Wed89°51°11%
- Thu94°59°9%
- Fri99°62°3%
- Sat96°62°3%
- Sun94°59°6%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 4, 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 · July 1–5
Fireweed Ignites
Magenta fireweed spires surge from burned and cleared slopes, their blooms climbing from base upward. July's signature color claims the disturbed ground.
Day 185 of 365 · Wedge 37 of 72
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
August is Newcastle's warmest stretch (~67°F) and January its coldest (~38°F); precipitation crests in November at 7.9 inches and ebbs in July to 0.5 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 38° | 7.5″ | 23 |
| February | 40° | 5.5″ | 20 |
| March | 43° | 5.6″ | 23 |
| April | 48° | 4.1″ | 20 |
| May | 55° | 3.1″ | 19 |
| June | 60° | 2.4″ | 16 |
| July | 66° | 0.5″ | 7 |
| August | 67° | 0.9″ | 6 |
| September | 60° | 2.4″ | 12 |
| October | 51° | 6.2″ | 19 |
| November | 44° | 7.9″ | 23 |
| December | 38° | 7.5″ | 24 |
Regional context
In Newcastle, NOAA NCEI 1991-2020 normals put January near 38°F and July near 66°F — a 28°F seasonal arc — with about 53.6 inches of precipitation over 211 rainy or snowy days.
Precipitation in Newcastle peaks in the cool season: November averages 7.9 inches across 22.6 storm-fed days, while July bottoms out at 0.5 inches over just 6.8 rainy days. That groups Newcastle with places like Renton, WA, Mercer Island, WA and Beaux Arts Village, WA on the same cool-season storm track.
Around late-May, Newcastle sheds its freezing nights — peas, lettuce, spinach, and radishes go into Newcastle's beds. Heat-demanding starts go out a fortnight on in Newcastle, after the soil warms and cold snaps clear. The season ends by early-October in Newcastle, once hard frosts set back in. Newcastle's low ground holds frost later into spring than Newcastle's benches, which run 3-5 days ahead.
Similar climates: Renton, WA, Mercer Island, WA, Beaux Arts Village, WA, Bryn Mawr-Skyway, WA, Bellevue, WA.
Frequently asked
- When does it freeze in Newcastle?
- Frost typically leaves Newcastle by mid-May and returns to Newcastle near mid-October.
- What is the rainy season in Newcastle?
- November is the wettest month in Newcastle, about 7.9 inches on average; the year totals roughly 54 inches.
- What is the warmest month in Newcastle?
- The warmest stretch in Newcastle comes in August, around 67°F on average.
- What is the coldest month in Newcastle?
- On average January is the chilliest month in Newcastle, about 38°F.
- When can I start a vegetable garden in Newcastle?
- Frost-hardy sowings begin at mid-May in Newcastle; warm-season starts follow two weeks on.
- How many rainy days does Newcastle get?
- Newcastle averages about 211 days with measurable rain or snow each year.
- What hardiness zone is Newcastle?
- Newcastle sits in the USDA zone set by January lows near 38°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?
- Today's sunrise and sunset times for Newcastle are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter 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, Washington occupies a warm-summer Mediterranean zone, with January means near 38°F and July around 66°F — a 28°F swing.
Newcastle sees close to 54 inches of precipitation annually, falling across some 211 wet days.
Latitude 47.5°N gives Newcastle its 28°F swing, and with it the rhythm of Newcastle's growing season.
ZIP codes in Newcastle
- 98059
- 98056