USDA Hardiness Zone 9b
Frost Dates for 95658 — Newcastle, California
NOAA 1991–2020 normals from Auburn, CA (1,292 ft), 4 miles northeast.
Updated
In Newcastle, the last spring frost (32°F) is around February 25 in half of years and has passed by April 7 in nine years out of ten. The first fall frost comes around December 5, as early as November 15 one year in ten, leaving a typical freeze-free season of 286 days (NOAA, Auburn, CA).
- Last spring frost
- February 25
- First fall frost
- December 5
- Growing season
- 286 days
- Hardiness zone
- 9b
50% probability
50% probability
freeze-free, 50%
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 25%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
5 of 20 observed
NOAA normal
Frost risk by date in Newcastle
Half of springs at Auburn, CA see their last 32°F night by February 25; only one in ten is past it by January 15, and one in ten still has one after April 7. Planting tender crops after March 14 leaves a 30% risk of a frost on them, after March 28 20%, and after April 7 10%. The 41 days between the even-odds date and the one-in-ten date is wider than at 89% of the 220 California stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by December 5 in half of years, as early as November 15 one year in ten, and holds off past December 31 one year in ten. A hard freeze of 28°F follows 17 days later, around December 22; in spring the one-in-ten date for 28°F is February 25, 41 days before the 32°F one. The freeze-free season lasts 286 days in a typical year, longer than at 57% of the 219 California stations; it reaches 330 days one year in ten and falls short of 236 one year in ten. On average 20 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 39 days longer, to about April 5, and return around November 19. A 24°F night is unusual: 30% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 2 | Mar 14 | Mar 23 | Mar 31 | Apr 5 | Apr 10 | Apr 15 | Apr 20 | Apr 30 |
| 32°F99% of yrs | Jan 15 | Jan 27 | Feb 5 | Feb 16 | Feb 25 | Mar 3 | Mar 14 | Mar 28 | Apr 7 |
| 28°F81% of yrs | Dec 19 | Dec 28 | Jan 2 | Jan 7 | Jan 13 | Jan 20 | Jan 31 | Feb 12 | Feb 25 |
| 24°F30% of yrs | too rare for a date | ||||||||
| 20°F5% of yrs | too rare for a date | ||||||||
| 16°F2% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 30 | Nov 6 | Nov 12 | Nov 16 | Nov 19 | Nov 23 | Nov 27 | Dec 1 | Dec 7 |
| 32°F99% of yrs | Nov 15 | Nov 22 | Nov 28 | Dec 1 | Dec 5 | Dec 9 | Dec 13 | Dec 19 | Dec 31 |
| 28°F81% of yrs | Dec 1 | Dec 7 | Dec 12 | Dec 16 | Dec 22 | Dec 27 | Jan 1 | Jan 8 | Jan 22 |
| 24°F30% of yrs | too rare for a date | ||||||||
| 20°F5% of yrs | too rare for a date | ||||||||
| 16°F2% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Auburn, CA, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 95658 →Compare Newcastle with another place →
Weather by month in Newcastle
July is the warmest month at Auburn, CA, averaging 93°F by day and 63°F at night; December is the coldest at 56°F and 37°F. From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 55% of years and March still brings one in 34% of years and April still brings one in 16% of years.
Warmth for growing adds up to 4,541 growing degree days a year (base 50°F), fewer than at 52% of the 283 California stations. 34% of them (1,522) have built up by the end of June, and July adds the most, 870. Precipitation totals 36.1 inches a year, most in January (7.0") and least in July (0.0"); May to September bring 7% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 56 | 38 | 7.0 | 87% | 6 | 29 |
| Feb | 59 | 40 | 6.5 | 55% | 3 | 62 |
| Mar | 63 | 42 | 6.1 | 34% | 1 | 130 |
| Apr | 68 | 45 | 2.8 | 16% | 1 | 211 |
| May | 77 | 52 | 1.7 | 0% | 0 | 442 |
| Jun | 86 | 58 | 0.4 | 0% | 0 | 648 |
| Jul | 93 | 63 | 0.0 | 0% | 0 | 870 |
| Aug | 92 | 63 | 0.1 | 0% | 0 | 849 |
| Sep | 87 | 60 | 0.2 | 0% | 0 | 695 |
| Oct | 77 | 52 | 1.4 | 2% | <1 | 443 |
| Nov | 64 | 43 | 3.1 | 34% | 1 | 140 |
| Dec | 56 | 37 | 6.8 | 85% | 8 | 23 |
Monthly normals 1991–2020 at Auburn, CA (1,292 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Colfax, CA, 18 miles northeast of Newcastle and 1,088 feet higher, has a last frost 37 days later (April 3), a first frost 11 days earlier (November 24), a season 53 days shorter.
When it snows in Newcastle, California
Measurable snow is rare here: only 5 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Auburn, CA, 3.8 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 95658
| When | What to do |
|---|---|
| December 17 – December 31 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 31 – January 14 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 28 – February 11 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 25 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 12 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 21 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 5 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 95658 is 4 miles from Auburn, CA, which stands at 1,292 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station; its figures are presented in full for 95648 (Lincoln). The 2023 USDA Plant Hardiness Zone Map lists ZIP 95658 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across California →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.