City	Sow outdoors	Last frost
San Jose	Dec 19 to Jan 16	Jan 2
Fresno	Dec 31 to Jan 28	Jan 14
Sacramento	Dec 29 to Jan 26	Jan 12
Bakersfield	Jan 17 to Feb 14	Jan 31
Stockton	Jan 22 to Feb 19	Feb 5
Riverside	Dec 26 to Jan 23	Jan 9
Irvine	Dec 22 to Jan 19	Jan 5
Fremont	Dec 18 to Jan 15	Jan 1
San Bernardino	Jan 13 to Feb 10	Jan 27
Fontana	Dec 21 to Jan 18	Jan 4
Modesto	Jan 17 to Feb 14	Jan 31
Moreno Valley	Jan 13 to Feb 10	Jan 27
Glendale	Dec 19 to Jan 16	Jan 2
Ontario	Dec 21 to Jan 18	Jan 4
Elk Grove	Jan 19 to Feb 16	Feb 2
Santa Rosa	Feb 11 to Mar 11	Feb 25
Rancho Cucamonga	Dec 21 to Jan 18	Jan 4
Oceanside	Jan 9 to Feb 6	Jan 23
Lancaster	Mar 20 to Apr 17	Apr 3
Roseville	Feb 8 to Mar 8	Feb 22
Palmdale	Feb 24 to Mar 24	Mar 10
Corona	Jan 3 to Jan 31	Jan 17
Salinas	Jan 15 to Feb 12	Jan 29
Hayward	Dec 19 to Jan 16	Jan 2
Sunnyvale	Dec 23 to Jan 20	Jan 6
Pomona	Dec 25 to Jan 22	Jan 8
Visalia	Jan 9 to Feb 6	Jan 23
Escondido	Dec 19 to Jan 16	Jan 2
Victorville	Mar 4 to Apr 1	Mar 18
Pasadena	Dec 25 to Jan 22	Jan 8
Santa Clara	Dec 29 to Jan 26	Jan 12
Clovis	Dec 31 to Jan 28	Jan 14
Simi Valley	Jan 10 to Feb 7	Jan 24
Vallejo	Jan 3 to Jan 31	Jan 17
Concord	Dec 26 to Jan 23	Jan 9
Fairfield	Jan 1 to Jan 29	Jan 15
Thousand Oaks	Dec 17 to Jan 14	Dec 31
Berkeley	Dec 20 to Jan 17	Jan 3
Antioch	Dec 29 to Jan 26	Jan 12
Menifee	Jan 14 to Feb 11	Jan 28
Temecula	Jan 19 to Feb 16	Feb 2
Richmond	Dec 21 to Jan 18	Jan 4
Murrieta	Jan 19 to Feb 16	Feb 2
Santa Maria	Jan 21 to Feb 18	Feb 4
Jurupa Valley	Dec 26 to Jan 23	Jan 9
Rialto	Dec 27 to Jan 24	Jan 10
West Covina	Dec 25 to Jan 22	Jan 8
Chico	Feb 18 to Mar 18	Mar 4
El Monte	Dec 21 to Jan 18	Jan 4
Vacaville	Feb 4 to Mar 4	Feb 18
San Mateo	Dec 15 to Jan 12	Dec 29
Burbank	Dec 19 to Jan 16	Jan 2
Hesperia	Feb 14 to Mar 14	Feb 28
Tracy	Feb 11 to Mar 11	Feb 25
El Cajon	Dec 23 to Jan 20	Jan 6
Daly City	Dec 16 to Jan 13	Dec 30
Merced	Feb 17 to Mar 17	Mar 3
Vista	Jan 16 to Feb 13	Jan 30
Chino	Jan 3 to Jan 31	Jan 17
Manteca	Jan 23 to Feb 20	Feb 6
Arden-Arcade	Dec 29 to Jan 26	Jan 12
San Marcos	Dec 19 to Jan 16	Jan 2
Indio	Dec 17 to Jan 14	Dec 31
Redding	Feb 17 to Mar 17	Mar 3
Hemet	Jan 17 to Feb 14	Jan 31
Folsom	Dec 29 to Jan 26	Jan 12
Carson	Dec 26 to Jan 23	Jan 9
Mission Viejo	Dec 23 to Jan 20	Jan 6
Rancho Cordova	Dec 29 to Jan 26	Jan 12
Santa Barbara	Dec 30 to Jan 27	Jan 13
Citrus Heights	Dec 29 to Jan 26	Jan 12
San Ramon	Feb 22 to Mar 22	Mar 8
Mountain View	Dec 23 to Jan 20	Jan 6
San Leandro	Dec 24 to Jan 21	Jan 7
Livermore	Feb 1 to Mar 1	Feb 15
Perris	Jan 14 to Feb 11	Jan 28
Redwood City	Jan 3 to Jan 31	Jan 17
Alhambra	Dec 21 to Jan 18	Jan 4
Upland	Dec 21 to Jan 18	Jan 4
Milpitas	Dec 29 to Jan 26	Jan 12
Carmichael	Dec 29 to Jan 26	Jan 12
Pittsburg	Dec 29 to Jan 26	Jan 12
Chino Hills	Jan 3 to Jan 31	Jan 17
Alameda	Dec 24 to Jan 21	Jan 7
Rocklin	Feb 11 to Mar 11	Feb 25
Napa	Jan 29 to Feb 26	Feb 12
Apple Valley	Mar 4 to Apr 1	Mar 18
Lake Elsinore	Jan 14 to Feb 11	Jan 28
Pleasanton	Feb 1 to Mar 1	Feb 15
Redlands	Jan 13 to Feb 10	Jan 27
Tulare	Jan 9 to Feb 6	Jan 23
Turlock	Dec 23 to Jan 20	Jan 6
Dublin	Feb 1 to Mar 1	Feb 15
Eastvale	Jan 3 to Jan 31	Jan 17
Walnut Creek	Dec 24 to Jan 21	Jan 7
Yuba City	Jan 1 to Jan 29	Jan 15
Lodi	Jan 26 to Feb 23	Feb 9
Madera	Jan 29 to Feb 26	Feb 12
Baldwin Park	Dec 21 to Jan 18	Jan 4
Camarillo	Dec 17 to Jan 14	Dec 31
Palo Alto	Jan 18 to Feb 15	Feb 1
Brentwood	Dec 29 to Jan 26	Jan 12
Davis	Jan 27 to Feb 24	Feb 10
Castro Valley	Dec 19 to Jan 16	Jan 2
Union City	Dec 24 to Jan 21	Jan 7
South San Francisco	Dec 15 to Jan 12	Dec 29
Laguna Niguel	Dec 23 to Jan 20	Jan 6
Porterville	Jan 6 to Feb 3	Jan 20
Woodland	Jan 24 to Feb 21	Feb 7
Hanford	Jan 24 to Feb 21	Feb 7
San Clemente	Dec 23 to Jan 20	Jan 6
Santa Cruz	Jan 15 to Feb 12	Jan 29
Beaumont	Jan 17 to Feb 14	Jan 31
Gilroy	Feb 10 to Mar 10	Feb 24
Montebello	Dec 21 to Jan 18	Jan 4
La Mesa	Dec 23 to Jan 20	Jan 6
Petaluma	Feb 14 to Mar 14	Feb 28
San Rafael	Dec 28 to Jan 25	Jan 11
Pico Rivera	Dec 21 to Jan 18	Jan 4
Cupertino	Dec 23 to Jan 20	Jan 6
Santee	Dec 23 to Jan 20	Jan 6
Highland	Jan 13 to Feb 10	Jan 27
Monterey Park	Dec 21 to Jan 18	Jan 4
Lincoln	Feb 11 to Mar 11	Feb 25
West Sacramento	Jan 19 to Feb 16	Feb 2
San Jacinto	Jan 17 to Feb 14	Jan 31
Yucaipa	Jan 13 to Feb 10	Jan 27
Arcadia	Dec 21 to Jan 18	Jan 4
Colton	Dec 27 to Jan 24	Jan 10
Palm Desert	Dec 17 to Jan 14	Dec 31
Cathedral City	Dec 26 to Jan 23	Jan 9
Delano	Jan 17 to Feb 14	Jan 31
Novato	Dec 28 to Jan 25	Jan 11
Diamond Bar	Dec 25 to Jan 22	Jan 8
Watsonville	Jan 14 to Feb 11	Jan 28
San Luis Obispo	Jan 17 to Feb 14	Jan 31
El Dorado Hills	Mar 17 to Apr 14	Mar 31
Aliso Viejo	Dec 23 to Jan 20	Jan 6
Glendora	Dec 25 to Jan 22	Jan 8
Los Banos	Jan 12 to Feb 9	Jan 26
Florin	Dec 29 to Jan 26	Jan 12
Rosemead	Dec 21 to Jan 18	Jan 4
Covina	Dec 25 to Jan 22	Jan 8
Poway	Dec 22 to Jan 19	Jan 5
Antelope	Dec 29 to Jan 26	Jan 12
Ceres	Jan 17 to Feb 14	Jan 31
North Highlands	Dec 29 to Jan 26	Jan 12
Newark	Dec 18 to Jan 15	Jan 1
Oakley	Dec 29 to Jan 26	Jan 12
Azusa	Dec 25 to Jan 22	Jan 8
Hollister	Feb 5 to Mar 5	Feb 19
Morgan Hill	Feb 10 to Mar 10	Feb 24
Coachella	Dec 17 to Jan 14	Dec 31
Palm Springs	Dec 18 to Jan 15	Jan 1
Rohnert Park	Feb 11 to Mar 11	Feb 25
El Centro	Dec 20 to Jan 17	Jan 3
Lompoc	Jan 6 to Feb 3	Jan 20
Danville	Feb 22 to Mar 22	Mar 8
Lathrop	Jan 23 to Feb 20	Feb 6
Vineyard	Dec 29 to Jan 26	Jan 12
French Valley	Jan 19 to Feb 16	Feb 2
Campbell	Jan 19 to Feb 16	Feb 2
San Bruno	Dec 28 to Jan 25	Jan 11
Altadena	Dec 25 to Jan 22	Jan 8
Rancho Palos Verdes	Dec 26 to Jan 23	Jan 9
La Quinta	Dec 17 to Jan 14	Dec 31
Adelanto	Mar 4 to Apr 1	Mar 18
Calexico	Dec 20 to Jan 17	Jan 3
Monrovia	Apr 14 to May 12	Apr 28
San Gabriel	Dec 21 to Jan 18	Jan 4
Wildomar	Jan 14 to Feb 11	Jan 28
Montclair	Dec 25 to Jan 22	Jan 8
Foothill Farms	Dec 29 to Jan 26	Jan 12
Pacifica	Dec 28 to Jan 25	Jan 11
Martinez	Feb 14 to Mar 14	Feb 28
La Puente	Dec 21 to Jan 18	Jan 4
Claremont	Dec 25 to Jan 22	Jan 8
Orangevale	Dec 29 to Jan 26	Jan 12
Temple City	Dec 21 to Jan 18	Jan 4
San Juan Capistrano	Dec 23 to Jan 20	Jan 6
Moorpark	Dec 17 to Jan 14	Dec 31
Oildale	Jan 17 to Feb 14	Jan 31
Pleasant Hill	Dec 24 to Jan 21	Jan 7
Desert Hot Springs	Feb 11 to Mar 11	Feb 25
San Dimas	Dec 25 to Jan 22	Jan 8
Menlo Park	Jan 18 to Feb 15	Feb 1
Los Gatos	Jan 19 to Feb 16	Feb 2
Fallbrook	Jan 19 to Feb 16	Feb 2
Foster City	Jan 3 to Jan 31	Jan 17
Goleta	Dec 28 to Jan 25	Jan 11
Dana Point	Dec 23 to Jan 20	Jan 6
Spring Valley	Dec 23 to Jan 20	Jan 6
Atwater	Feb 17 to Mar 17	Mar 3
Fair Oaks	Dec 29 to Jan 26	Jan 12
Burlingame	Dec 15 to Jan 12	Dec 29
Banning	Jan 17 to Feb 14	Jan 31
Santa Paula	Dec 17 to Jan 14	Dec 31
San Pablo	Dec 21 to Jan 18	Jan 4
Seaside	Dec 19 to Jan 16	Jan 2
El Paso de Robles	Mar 1 to Mar 29	Mar 15
Orcutt	Jan 21 to Feb 18	Feb 4
Los Altos	Dec 23 to Jan 20	Jan 6
Saratoga	Jan 19 to Feb 16	Feb 2
La Verne	Dec 25 to Jan 22	Jan 8
Laguna Hills	Dec 23 to Jan 20	Jan 6
Atascadero	Mar 1 to Mar 29	Mar 15
Suisun City	Jan 1 to Jan 29	Jan 15
San Lorenzo	Dec 19 to Jan 16	Jan 2
Eastern Goleta Valley	Dec 28 to Jan 25	Jan 11
San Carlos	Jan 3 to Jan 31	Jan 17
Monterey	Dec 18 to Jan 15	Jan 1
East Palo Alto	Jan 18 to Feb 15	Feb 1
Belmont	Jan 3 to Jan 31	Jan 17
East Niles	Jan 17 to Feb 14	Jan 31
Temescal Valley	Jan 14 to Feb 11	Jan 28
Ridgecrest	Feb 25 to Mar 25	Mar 11
Brawley	Jan 2 to Jan 30	Jan 16
Walnut	Dec 25 to Jan 22	Jan 8
Lemoore	Feb 10 to Mar 10	Feb 24
Sanger	Jan 16 to Feb 13	Jan 30
Reedley	Jan 16 to Feb 13	Jan 30
Galt	Jan 26 to Feb 23	Feb 9
Patterson	Jan 17 to Feb 14	Jan 31
Riverbank	Jan 17 to Feb 14	Jan 31
Wasco	Jan 17 to Feb 14	Jan 31
Benicia	Jan 3 to Jan 31	Jan 17
Soledad	Apr 9 to May 7	Apr 23
Hercules	Jan 3 to Jan 31	Jan 17
El Cerrito	Dec 20 to Jan 17	Jan 3
Dinuba	Jan 9 to Feb 6	Jan 23
Twentynine Palms	Jan 10 to Feb 7	Jan 24
Windsor	Feb 16 to Mar 16	Mar 2
South Pasadena	Dec 25 to Jan 22	Jan 8
West Whittier-Los Nietos	Dec 21 to Jan 18	Jan 4
Mountain House	Jan 5 to Feb 2	Jan 19
Lafayette	Dec 24 to Jan 21	Jan 7
Eureka	Feb 8 to Mar 8	Feb 22
Loma Linda	Jan 13 to Feb 10	Jan 27
Norco	Jan 3 to Jan 31	Jan 17
Barstow	Feb 8 to Mar 8	Feb 22
Selma	Jan 16 to Feb 13	Jan 30
Bloomington	Dec 27 to Jan 24	Jan 10
Bay Point	Dec 26 to Jan 23	Jan 9
Shafter	Feb 6 to Mar 6	Feb 20
Ladera Ranch	Dec 23 to Jan 20	Jan 6
East San Gabriel	Dec 21 to Jan 18	Jan 4
San Fernando	Dec 19 to Jan 16	Jan 2
Rosemont	Dec 29 to Jan 26	Jan 12
Marina	Jan 21 to Feb 18	Feb 4
Oakdale	Jan 17 to Feb 14	Jan 31
Linda	Jan 28 to Feb 25	Feb 11
Millbrae	Dec 15 to Jan 12	Dec 29
Duarte	Apr 14 to May 12	Apr 28
Ramona	Mar 5 to Apr 2	Mar 19
Ashland	Dec 19 to Jan 16	Jan 2
American Canyon	Feb 19 to Mar 19	Mar 5
Laguna Beach	Dec 23 to Jan 20	Jan 6
Corcoran	Feb 1 to Mar 1	Feb 15
Imperial	Dec 31 to Jan 28	Jan 14
Rancho San Diego	Dec 23 to Jan 20	Jan 6
West Puente Valley	Dec 21 to Jan 18	Jan 4
Calabasas	Jan 10 to Feb 7	Jan 24
Winter Gardens	Dec 23 to Jan 20	Jan 6
West Carson	Dec 26 to Jan 23	Jan 9
Yucca Valley	Feb 28 to Mar 28	Mar 14
Lakeside	Dec 23 to Jan 20	Jan 6
Valinda	Dec 25 to Jan 22	Jan 8
Granite Bay	Feb 11 to Mar 11	Feb 25
Stevenson Ranch	Dec 25 to Jan 22	Jan 8
Greenfield	Feb 9 to Mar 9	Feb 23
Dixon	Jan 27 to Feb 24	Feb 10
Rosamond	Mar 20 to Apr 17	Apr 3
Oroville	Jan 16 to Feb 13	Jan 30
East Hemet	Dec 27 to Jan 24	Jan 10

Questions

When should I plant swiss chard in California?

In San Jose, sow outdoors from December 19 to January 16. Across California the window opens between December 18 and December 17, depending on the local last frost.

How is this date worked out?

Sow outdoors from 2 weeks before to 2 weeks after the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.