When to plant in Porterville, CA
USDA Zone 9bEverything below — frost dates, hardiness zone, and what to plant when in Porterville, California — is derived from the closest NOAA station with complete climate normals.
With about 327 frost-free days, Porterville supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. Zone 9b is warm enough that Porterville can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in Porterville is now 12 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
PORTERVILLE · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Porterville’s own odds, recorded at PORTERVILLE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 7 | Feb 26 | Jan 25 | Nov 10 | Nov 28 | Dec 14 |
| 32°F | Feb 22 | Jan 20 | Dec 25 | Nov 26 | Dec 13 | Jan 6 |
| 28°F | Jan 22 | Dec 31 | Dec 13 | Dec 4 | Dec 23 | Jan 13 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.
Full-year planting calendar
Each bar is the exact window to take a planting action in Porterville, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 35 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Porterville planting FAQ
When is the last spring frost in Porterville, CA?
On average, the last spring frost in Porterville is around January 20 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Porterville, CA?
In Porterville, the first 32°F freeze of fall lands around December 13 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Porterville in?
Porterville is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Porterville?
There are roughly 327 frost-free days in Porterville (a long growing season), running from the average last frost around January 20 to the first fall frost near December 13.
When should I plant tomatoes in Porterville?
In Porterville, start tomato seeds indoors around November 25–December 9, then transplant seedlings outdoors around January 27 once the danger of frost has passed.
Never miss a window in Porterville
An email when it’s time to start seeds, transplant, and sow — timed to Porterville’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at PORTERVILLE, 1 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Porterville, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00047077. Retrieved from https://blissgarden.com/california/porterville.