Frost Dates: First and last frost dates for Valley Falls, OR

ℹ️ How to read these charts for the spring

As spring unfolds, the risk of frost gradually decreases each day until your tender plants are finally safe. The probabilities shown in the chart help you make smart decisions about when to plant.

While frost typically forms at 32°F, tender plants can be damaged even when temperatures are slightly higher. Air temperatures are often measured several feet above the ground, but temperatures at plant level can be several degrees colder. Protected areas like porches help by blocking radiational cooling. Given these variables, we consider 36°F the "caution zone" for frost-sensitive plants.

Key dates for your spring planting:

  • By July 14, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
  • Around June 29, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
  • Before June 19, there's still an 80% risk of frost — too early for tomatoes and other tender plants unless you're prepared to protect them

If the 10-day forecast shows no temperatures below 40°F, you might safely plant earlier than the above dates suggest. Many gardeners watch for this weather window to get a head start on the growing season.

In the Spring
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
Last 16° Apr 21 Apr 10 Apr 2 Mar 26 Mar 20 Mar 14 Mar 7 Feb 27 Feb 16
Last 20° May 7 Apr 30 Apr 25 Apr 20 Apr 16 Apr 12 Apr 7 Apr 2 Mar 26
Last 24° May 28 May 18 May 12 May 6 Apr 30 Apr 25 Apr 19 Apr 12 Apr 3
Last 28° Jun 13 Jun 5 May 31 May 26 May 22 May 18 May 13 May 8 Apr 30
Last 32° Jul 3 Jun 26 Jun 21 Jun 17 Jun 13 Jun 8 Jun 4 May 30 May 23
Last 36° Jul 14 Jul 9 Jul 5 Jul 2 Jun 29 Jun 26 Jun 23 Jun 19 Jun 14

ℹ️ How to read these charts for the fall

As summer ends in Valley Falls, OR, nighttime temperatures begin to drop, and your risk of frost increases with each passing day. Knowing when to expect frost helps you harvest sensitive crops and extend your growing season with protection methods.

The chart below shows the probability of experiencing specific temperatures on various dates. Here's what this means for your garden:

1
Early warning: Around August 13, there's a 20% chance of 32°F — start monitoring forecasts and have plant covers ready
2
Decision time: By September 1, there's a 50% chance of frost — harvest tomatoes, peppers, and other tender crops or prepare protection
3
Last chance: By September 20, there's an 80% chance of seeing 32°F — most tender plants will be damaged without protection
4
Another perspective: You have only a 1 in 5 chance of making it past September 20 without a freezing night

These probabilities help you time your end-of-season harvests and know when to apply protective measures like row covers, cloches, or cold frames to extend your harvest.

In the Fall
Temperature 10% 20% 30% 40% 50% 60% 70% 80% 90%
First 16° Oct 11 Oct 20 Oct 27 Nov 2 Nov 8 Nov 14 Nov 20 Nov 27 Dec 7
First 20° Oct 2 Oct 10 Oct 17 Oct 22 Oct 27 Nov 1 Nov 6 Nov 13 Nov 21
First 24° Sep 4 Sep 17 Sep 25 Oct 3 Oct 10 Oct 17 Oct 25 Nov 2 Nov 15
First 28° Aug 13 Aug 24 Sep 1 Sep 7 Sep 14 Sep 20 Sep 27 Oct 5 Oct 16
First 32° Aug 3 Aug 13 Aug 20 Aug 27 Sep 1 Sep 7 Sep 13 Sep 20 Sep 30
First 36° Jul 29 Aug 5 Aug 11 Aug 16 Aug 20 Aug 25 Aug 30 Sep 5 Sep 13

📍 Frost Dates for other nearby locations

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Data is provided by the NOAA National Centers for Environmental Information.