Will it frost tonight?
Tonight's low for your ZIP code, whether to cover plants or protect pipes, and the coming week's nights, from the National Weather Service hourly forecast.
Frost, freeze and hard freeze
- Frost (33–36°F): frost forms on plants on clear, calm nights. Cover tender plants and bring pots in.
- Freeze (32°F and below): kills tomatoes, peppers, basil, squash and other tender plants. Disconnect garden hoses.
- Hard freeze (28°F and below): ends most of the garden, including hardier crops. Shut off and drain outdoor faucets.
- 20°F and below: pipes on outside walls and in unheated spaces can freeze. Let faucets drip overnight.
How to cover plants
Before sunset, drape a sheet, blanket or frost cloth over plants all the way to the ground, so it holds in the warmth the soil gives off at night. Don't let plastic touch the leaves. Take covers off in the morning once it's above freezing.
When is the first frost usually? See the planting calendar for your city for typical first and last frost dates, or the soil temperature map for how fast the ground is cooling.
Frequently asked questions
Can it frost when the temperature is above 32°F?
Yes. On clear, calm nights, plants, grass and car windows lose heat faster than the air, so frost often forms when the forecast low is 33–36°F. That is why the National Weather Service issues frost advisories for lows in that range.
What temperature kills tomato and pepper plants?
Tender plants such as tomatoes, peppers, basil and squash are damaged by frost and killed by a freeze of 32°F or below. A hard freeze, 28°F or colder for a few hours, also ends hardier crops and most annual flowers.
When should I drip my faucets?
Pipes in unheated spaces and on outside walls are at risk once it drops to about 20°F. On those nights, let faucets on outside walls drip and open the cabinet doors under sinks. Disconnect garden hoses whenever a freeze is forecast.