Frost Dates: First and last frost dates for Sidney, IA
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 May 10, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
- Around April 27, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
- Before April 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.
| Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| Last 16° | Mar 31 | Mar 23 | Mar 18 | Mar 13 | Mar 8 | Mar 4 | Feb 27 | Feb 21 | Feb 13 |
| Last 20° | Apr 1 | Mar 27 | Mar 23 | Mar 20 | Mar 17 | Mar 15 | Mar 12 | Mar 8 | Mar 3 |
| Last 24° | Apr 12 | Apr 7 | Apr 3 | Mar 31 | Mar 29 | Mar 26 | Mar 23 | Mar 19 | Mar 14 |
| Last 28° | Apr 19 | Apr 15 | Apr 12 | Apr 9 | Apr 7 | Apr 4 | Apr 1 | Mar 29 | Mar 25 |
| Last 32° | May 1 | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 14 | Apr 10 | Apr 7 | Apr 2 |
| Last 36° | May 10 | May 6 | May 3 | Apr 30 | Apr 27 | Apr 25 | Apr 22 | Apr 19 | Apr 14 |
ℹ️ How to read these charts for the fall
As summer ends in Sidney, IA, 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:
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.
| Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| First 16° | Nov 5 | Nov 11 | Nov 16 | Nov 20 | Nov 23 | Nov 27 | Nov 30 | Dec 5 | Dec 11 |
| First 20° | Oct 27 | Nov 2 | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 22 | Nov 27 | Dec 3 |
| First 24° | Oct 23 | Oct 28 | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 24 |
| First 28° | Oct 10 | Oct 16 | Oct 21 | Oct 24 | Oct 28 | Oct 31 | Nov 4 | Nov 8 | Nov 14 |
| First 32° | Sep 30 | Oct 5 | Oct 9 | Oct 12 | Oct 14 | Oct 17 | Oct 20 | Oct 24 | Oct 29 |
| First 36° | Sep 19 | Sep 24 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 19 |
📍 Frost Dates for other nearby locations
- Shenandoah, IA 15.7 mi
- Nebraska City, NE 19.9 mi
- Glenwood, IA 20.6 mi
- Tarkio, MO 27.3 mi
- Auburn, NE 28.8 mi
- Red Oak, IA 30.3 mi
- Weeping Water, NE 37.7 mi
- Oakland, IA 40.5 mi
- Clarinda, IA 40.7 mi
- Syracuse, NE 40.9 mi
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Data is provided by the NOAA National Centers for Environmental Information.