City	Sow outdoors	Last frost
New York	Mar 18 to Apr 15	Apr 1
Buffalo	Apr 10 to May 8	Apr 24
Yonkers	Apr 6 to May 4	Apr 20
Rochester	Apr 10 to May 8	Apr 24
Syracuse	Apr 15 to May 13	Apr 29
Albany	Apr 13 to May 11	Apr 27
New Rochelle	Apr 6 to May 4	Apr 20
Cheektowaga	Apr 10 to May 8	Apr 24
Mount Vernon	Mar 18 to Apr 15	Apr 1
Schenectady	Apr 13 to May 11	Apr 27
Utica	Apr 17 to May 15	May 1
White Plains	Mar 29 to Apr 26	Apr 12
Hempstead	Mar 19 to Apr 16	Apr 2
Tonawanda Town	Apr 22 to May 20	May 6
Levittown	Mar 20 to Apr 17	Apr 3
Troy	Apr 5 to May 3	Apr 19
Irondequoit	Apr 10 to May 8	Apr 24
Niagara Falls	Apr 12 to May 10	Apr 26
Kiryas Joel	Mar 27 to Apr 24	Apr 10
Binghamton	Apr 18 to May 16	May 2
West Seneca	Apr 10 to May 8	Apr 24
Freeport	Mar 24 to Apr 21	Apr 7
Hicksville	Mar 19 to Apr 16	Apr 2
West Babylon	Mar 23 to Apr 20	Apr 6
Coram	Mar 21 to Apr 18	Apr 4
Valley Stream	Mar 19 to Apr 16	Apr 2
Central Islip	Mar 27 to Apr 24	Apr 10
Brighton	Apr 10 to May 8	Apr 24
Elmont	Mar 19 to Apr 16	Apr 2
Commack	Mar 26 to Apr 23	Apr 9
East Meadow	Mar 19 to Apr 16	Apr 2
Long Beach	Mar 24 to Apr 21	Apr 7
Spring Valley	Apr 6 to May 4	Apr 20
New City	Apr 11 to May 9	Apr 25
Uniondale	Mar 19 to Apr 16	Apr 2
Ithaca	Apr 27 to May 25	May 11
Baldwin	Mar 24 to Apr 21	Apr 7
Huntington Station	Mar 26 to Apr 23	Apr 9
Poughkeepsie	Apr 7 to May 5	Apr 21
Port Chester	Mar 29 to Apr 26	Apr 12
Harrison	Mar 29 to Apr 26	Apr 12
Oceanside	Mar 24 to Apr 21	Apr 7
Rome	Apr 22 to May 20	May 6
Centereach	Mar 27 to Apr 24	Apr 10
Bay Shore	Mar 21 to Apr 18	Apr 4
Franklin Square	Mar 19 to Apr 16	Apr 2
Middletown	Apr 7 to May 5	Apr 21
North Tonawanda	Apr 22 to May 20	May 6
Saratoga Springs	Apr 18 to May 16	May 2
Glen Cove	Mar 19 to Apr 16	Apr 2
Newburgh	Apr 15 to May 13	Apr 29
Shirley	Apr 4 to May 2	Apr 18
Monsey	Apr 5 to May 3	Apr 19
Jamestown	Apr 24 to May 22	May 8
Ossining	Apr 11 to May 9	Apr 25
Deer Park	Mar 23 to Apr 20	Apr 6
Lindenhurst	Mar 23 to Apr 20	Apr 6
West Islip	Mar 23 to Apr 20	Apr 6
Holbrook	Mar 27 to Apr 24	Apr 10
Plainview	Mar 23 to Apr 20	Apr 6
Elmira	Apr 22 to May 20	May 6
Auburn	Apr 18 to May 16	May 2
Peekskill	Apr 16 to May 14	Apr 30
Rockville Centre	Mar 24 to Apr 21	Apr 7
Medford	Apr 4 to May 2	Apr 18
Dix Hills	Mar 26 to Apr 23	Apr 9
Smithtown	Mar 27 to Apr 24	Apr 10
Kingston	Apr 30 to May 28	May 14
Watertown	Apr 18 to May 16	May 2
Copiague	Mar 23 to Apr 20	Apr 6
Garden City	Mar 19 to Apr 16	Apr 2
Rotterdam	Apr 13 to May 11	Apr 27
Massapequa	Mar 20 to Apr 17	Apr 3
Merrick	Mar 20 to Apr 17	Apr 3
Selden	Mar 21 to Apr 18	Apr 4
Mineola	Mar 19 to Apr 16	Apr 2
East Patchogue	Mar 27 to Apr 24	Apr 10
Lynbrook	Mar 24 to Apr 21	Apr 7
North Bellmore	Mar 20 to Apr 17	Apr 3
Niskayuna	Apr 13 to May 11	Apr 27
Hauppauge	Mar 27 to Apr 24	Apr 10
West Hempstead	Mar 19 to Apr 16	Apr 2
Eastchester	Apr 6 to May 4	Apr 20
North Bay Shore	Mar 23 to Apr 20	Apr 6
North Amityville	Mar 23 to Apr 20	Apr 6
Lockport	Apr 12 to May 10	Apr 26
East Massapequa	Mar 20 to Apr 17	Apr 3
Huntington	Mar 26 to Apr 23	Apr 9
Nanuet	Apr 6 to May 4	Apr 20

Questions

When should I plant swiss chard in New York?

In New York, sow outdoors from March 18 to April 15. Across New York the window opens between March 18 and April 30, 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.