Zone 7a

The coldest winter night here averages 0 to 5°F1. Frost dates vary more than that suggests.

ZIP codes: 4,877
Weather stations: 865
Last reviewed: 2026-11-02

Your zone tells you how cold winter gets. It does not tell you when to plant.

Typical last frost: Apr 16most ZIPs Apr 4 – Apr 28
Typical first frost: Oct 25most ZIPs Oct 16 – Nov 2
Spread in spring: 24 daysbetween early and late ZIPs

Last spring frostmedian Apr 16Full range across the zone: Mar 25 to Jun 11Most of the zone (10th to 90th percentile): Apr 4 to Apr 28Zone median: Apr 16
First fall frostmedian Oct 25Full range across the zone: Sep 10 to Nov 17Most of the zone (10th to 90th percentile): Oct 16 to Nov 2Zone median: Oct 25

Frost-free season (median)

Figure 1. When frosts fall across zone 7a: the full range (pale), most ZIP codes (10th to 90th percentile, solid) and the median (marker). From 865 NOAA stations matched to 3,807 ZIP codes.

Zone and frost date are different things. The zone comes from the coldest winter night; frost dates come from spring and fall temperatures at weather stations2. Your own dates can sit anywhere in the range above, so the calendar for your ZIP is the better guide.

When to plant in zone 7a

Each crop uses its primary extension source, applied to this zone's frost spread. Rules written for another state are labelled with their source.

TomatoesStart indoors across most of the zone: Feb 8 to Mar 3Start indoors at the zone median: Feb 20 (Oregon State, central OR)Transplant outdoors across most of the zone: Apr 18 to May 12Transplant outdoors at the zone median: Apr 30 (Colorado State)
PeppersStart indoors across most of the zone: Feb 22 to Mar 17Start indoors at the zone median: Mar 5 (Oregon State, central OR)Transplant outdoors across most of the zone: Apr 18 to May 12Transplant outdoors at the zone median: Apr 30 (Colorado State)
CucumbersStart indoors across most of the zone: Mar 21 to Apr 14Start indoors at the zone median: Apr 2 (Oregon State, central OR)Transplant outdoors across most of the zone: Apr 11 to May 5Transplant outdoors at the zone median: Apr 23 (Oregon State, central OR)Sow outdoors across most of the zone: Apr 4 to Apr 28Sow outdoors at the zone median: Apr 16 (Colorado State)
ZucchiniStart indoors across most of the zone: Mar 28 to Apr 21Start indoors at the zone median: Apr 9 (Oregon State, central OR)Transplant outdoors across most of the zone: Apr 18 to May 12Transplant outdoors at the zone median: Apr 30 (Oregon State, central OR)Sow outdoors across most of the zone: Apr 4 to Apr 28Sow outdoors at the zone median: Apr 16 (Colorado State)
BeansStart indoors across most of the zone: Mar 14 to Apr 7Start indoors at the zone median: Mar 26 (Oregon State, central OR)Transplant outdoors across most of the zone: Apr 11 to May 5Transplant outdoors at the zone median: Apr 23 (Oregon State, central OR)Sow outdoors across most of the zone: Apr 4 to Apr 28Sow outdoors at the zone median: Apr 16 (Colorado State)
PeasStart indoors across most of the zone: Feb 8 to Mar 3Start indoors at the zone median: Feb 20 (Oregon State, central OR)Transplant outdoors across most of the zone: Mar 7 to Mar 31Transplant outdoors at the zone median: Mar 19 (Oregon State, central OR)Sow outdoors across most of the zone: Mar 7 to Apr 14Sow outdoors at the zone median: Mar 19 to Apr 2 (Colorado State)
LettuceStart indoors across most of the zone: Feb 15 to Mar 10Start indoors at the zone median: Feb 27 (Oregon State, central OR)Transplant outdoors across most of the zone: Mar 21 to Apr 14Transplant outdoors at the zone median: Apr 2 (Oregon State, central OR)Sow outdoors across most of the zone: Mar 7 to Apr 14Sow outdoors at the zone median: Mar 19 to Apr 2 (Colorado State)
CarrotsSow outdoors across most of the zone: Mar 21 to Apr 28Sow outdoors at the zone median: Apr 2 to Apr 16 (Colorado State)
OnionsStart indoors across most of the zone: Dec 14 to Jan 7Start indoors at the zone median: Dec 26 (Oregon State, central OR)Transplant outdoors across most of the zone: Feb 22 to Mar 17Transplant outdoors at the zone median: Mar 5 (Oregon State, central OR)Sow outdoors across most of the zone: Mar 7 to Apr 14Sow outdoors at the zone median: Mar 19 to Apr 2 (Colorado State)
GarlicPlant for fall across most of the zone: Oct 23 to Nov 16Plant for fall at the zone median: Nov 1 to Nov 8 (Wisconsin)
PotatoesSow outdoors across most of the zone: Mar 21 to Apr 28Sow outdoors at the zone median: Apr 2 to Apr 16 (Colorado State)
BasilNo sourced window

Start indoors
Plant outdoors
Range across the zone
Frost-free season (median)
Spring frost risk (90% to 10%)
Fall frost risk (10% to 90%)

Figure 2. Planting windows across zone 7a. Solid and dashed bars: the window at the zone's median frost dates. Pale bars: where the same window falls across most of the zone's ZIP codes.

Table 1. Planting windows in zone 7a.
Crop	What	Zone median	Across most of the zone	Source
Tomatoes	Start indoors	Feb 20	Feb 8 – Mar 3	Oregon State, central OR3
Tomatoes	Transplant outdoors	Apr 30	Apr 18 – May 12	Colorado State4
Peppers	Start indoors	Mar 5	Feb 22 – Mar 17	Oregon State, central OR3
Peppers	Transplant outdoors	Apr 30	Apr 18 – May 12	Colorado State4
Cucumbers	Start indoors	Apr 2	Mar 21 – Apr 14	Oregon State, central OR3
	Transplant outdoors	Apr 23	Apr 11 – May 5	Oregon State, central OR3
	Sow outdoors	Apr 16	Apr 4 – Apr 28	Colorado State4
Zucchini	Start indoors	Apr 9	Mar 28 – Apr 21	Oregon State, central OR3
	Transplant outdoors	Apr 30	Apr 18 – May 12	Oregon State, central OR3
	Sow outdoors	Apr 16	Apr 4 – Apr 28	Colorado State4
Beans	Start indoors	Mar 26	Mar 14 – Apr 7	Oregon State, central OR3
	Transplant outdoors	Apr 23	Apr 11 – May 5	Oregon State, central OR3
	Sow outdoors	Apr 16	Apr 4 – Apr 28	Colorado State4
Peas	Start indoors	Feb 20	Feb 8 – Mar 3	Oregon State, central OR3
	Transplant outdoors	Mar 19	Mar 7 – Mar 31	Oregon State, central OR3
	Sow outdoors	Mar 19 – Apr 2	Mar 7 – Apr 14	Colorado State4
Lettuce	Start indoors	Feb 27	Feb 15 – Mar 10	Oregon State, central OR3
	Transplant outdoors	Apr 2	Mar 21 – Apr 14	Oregon State, central OR3
	Sow outdoors	Mar 19 – Apr 2	Mar 7 – Apr 14	Colorado State4
Carrots	Sow outdoors	Apr 2 – Apr 16	Mar 21 – Apr 28	Colorado State4
Onions	Start indoors	Dec 26	Dec 14 – Jan 7	Oregon State, central OR3
	Transplant outdoors	Mar 5	Feb 22 – Mar 17	Oregon State, central OR3
	Sow outdoors	Mar 19 – Apr 2	Mar 7 – Apr 14	Colorado State4
Garlic	Plant for fall	Nov 1 – Nov 8	Oct 23 – Nov 16	Wisconsin5
Potatoes	Sow outdoors	Apr 2 – Apr 16	Mar 21 – Apr 28	Colorado State4
Basil	No frost-relative rule is published; sources give conditions instead (see the crop page).

Sources

PRISM Group, Oregon State University, 2023 USDA Plant Hardiness Zone Map ZIP code data (PHZM 2023), 2023-11-15. Retrieved 2026-11-02.
NOAA National Centers for Environmental Information, U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), 2021. Retrieved 2026-11-02.
Oregon State University Extension Service, When to start seeds indoors in central Oregon, reviewed 2024. Retrieved 2026-11-02.
Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720), reviewed September 2024. Retrieved 2026-11-02.
University of Wisconsin–Madison Division of Extension, Wisconsin Horticulture, Garlic, Allium sativum, Rev: 10/2023. Retrieved 2026-11-02.