USDA Hardiness Zone 5a
Frost Dates for 82930 — Evanston, Wyoming
Averages from Evanston 1 E, Wy US, the nearest reporting station, 2.3 miles away.
Plant tender crops after June 12, and expect the first autumn freeze around September 12. That leaves about 90 frost-free days.
- Last spring frost
- June 12
- First fall frost
- September 12
- Growing season
- 90 days
- Hardiness zone
- 5a
50% probability
50% probability
frost-free
-20 to -15°F annual low
Planting calendar for 82930
| When | What to do |
|---|---|
| April 3 – April 17 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| April 17 – May 1 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| May 15 – May 29 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| June 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by June 20 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by August 29 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| September 12 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after June 12 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Evanston, Wyoming are past their last freeze. Harvest before September 12, which leaves roughly 90 frost-free days.
ZIP 82930 sits in USDA hardiness zone 5a, meaning the average coldest night of the year falls between -20 to -15°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.