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Will it freeze in Newcastle in the next 7 nights?
No overnight lows at or below 32°F are forecast in Newcastle during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 46°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM PST to Fri, Nov 6, 6:00 AM PST.
No nights at or below 36°F in the National Weather Service forecast for the next 7 nights.
- Tonight 46°F Above 36°F · Mostly Cloudy then Chance Light Rain
- Fri, Nov 6 50°F Above 36°F · Light Rain
- Sat, Nov 7 50°F Above 36°F · Light Rain
- Sun, Nov 8 42°F Above 36°F · Partly Cloudy
- Mon, Nov 9 48°F Above 36°F · Light Rain Likely
- Tue, Nov 10 51°F Above 36°F · Light Rain Likely
- Wed, Nov 11 49°F Above 36°F · Chance Light Rain
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Newcastle
The median first fall hard-freeze date (28°F) is December 6, from NOAA’s 1991–2020 Climate Normals at Renton Municipal Airport. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Mar 21 · Apr 6 · Apr 25 | Oct 17 · Oct 31 · Nov 17 | 207 days |
| 32°F freeze | Feb 19 · Mar 13 · Mar 31 | Oct 29 · Nov 16 · Dec 9 | 248 days |
| 28°F hard freeze | Jan 1 · Feb 13 · Mar 6 | Nov 11 · Dec 6 · Jan 9 | 301 days |
Average high temperature by month
1991–2020 normals at Renton Municipal Airport
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Newcastle, WA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Renton Municipal Airport (station USW00094248, elevation 29 ft), 3.5 mi from Newcastle. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Newcastle
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Mercer Island, WA | 3.7 mi | Mar 13 | Nov 17 |
| Renton, WA | 3.7 mi | Mar 13 | Nov 16 |
| Bellevue, WA | 4.3 mi | Mar 8 | Nov 23 |
| Issaquah, WA | 5.6 mi | Mar 13 | Nov 16 |
| Tukwila, WA | 6.2 mi | Mar 2 | Nov 23 |
| Sammamish, WA | 7.5 mi | Mar 30 | Nov 7 |
| SeaTac, WA | 8.7 mi | Mar 2 | Nov 23 |
| Burien, WA | 9.3 mi | Mar 2 | Nov 23 |
| Kent, WA | 9.9 mi | Mar 20 | Nov 10 |
| Redmond, WA | 11 mi | Mar 8 | Nov 23 |
Frequently asked questions
When is the last frost in Newcastle?
On average, the last spring frost (32°F) in Newcastle is around March 13. In about 1 year in 10 it comes after March 31, and in 9 years in 10 it comes after February 19.
When is the first frost in Newcastle?
The first fall frost (32°F) usually arrives around November 16. There’s a 10% chance of a freeze by October 29 and a 90% chance by December 9.
Can it frost in Newcastle after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 6.
What growing zone is Newcastle?
Newcastle is in USDA Plant Hardiness Zone 8b (average annual extreme minimum temperature 15 to 20°F), based on the 2023 USDA map for ZIP code 98006. See growing zones in Washington.
More: all Washington frost dates · Washington growing zones · frost vs. freeze