U.S. Frost Dates by Weather Station

NOAA station USC00263957 · Nevada

Frost Dates for Imlay, NV

NOAA weather station Imlay (USC00263957), Nevada · elevation 4260 ft (1298 m) · hardiness zone 6a*

  • Lower-risk planting dateafter June 8only 1 spring in 10 still has a frost later
  • Typical last frostMay 1750% chance of a frost after it
  • Typical first fall frostSeptember 2750% chance of a frost before it
  • Frost-free season131 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Imlay, NVSpring: a frost after April 30 in 9 years out of 10, after May 17 in half of the years, after June 8 in 1 year out of 10. Fall: the first frost comes before September 13 in 1 year out of 10, before September 27 in half of the years, before October 9 in 9 years out of 10. Typical frost-free season: 131 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 17First frost ~Sep 27Frost season at Imlay, NVSpring: a frost after April 30 in 9 years out of 10, after May 17 in half of the years, after June 8 in 1 year out of 10. Fall: the first frost comes before September 13 in 1 year out of 10, before September 27 in half of the years, before October 9 in 9 years out of 10. Typical frost-free season: 131 days.JFMAMJJASONDLast frost ~May 17First frost ~Sep 27
frost likely chance fading 90% → 10% frost-free in a typical yearThe year at a glance. Blue: frost is likely; the gradient fades as the chance drops from 90% to 10%; green: the frost-free part of a typical year.

Frost dates (32°F)

Probability of frost, based on 29 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 8September 13
50% (typical)May 17September 27
90% (likely)April 30October 9
Frost-free season (32°F, 50% chance)
131 days
Hard frost (28°F), last in spring, 50% chance after
May 3
Hard frost (28°F), first in fall, 50% chance before
October 6

The last 15 years (2006–2020 normals)

Typical last frost May 20 (3 days later than the 30-year normal), typical first fall frost September 26 (1 day earlier). Frost-free season 130 days.

A shorter, more recent NOAA period. The 30-year normals above remain the main reference: 15 years carry more year-to-year noise.

Add these dates to your calendar Yearly reminders for the typical last frost, the lower-risk planting date and the typical first fall frost (.ics).

How the chance of frost changes with the date

Spring at Imlay: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 8, 20% June 2, 30% May 28, 40% May 22, 50% May 17, 60% May 13, 70% May 9, 80% May 4, 90% April 30. Observed last spring frost in recent years: 2022 June 19, 2023 May 8.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 8May 17Apr 302022: June 192023: May 8Fall at Imlay: chance of a frost before this dateFall, chance of a frost before the date: 10% September 13, 20% September 18, 30% September 22, 40% September 25, 50% September 27, 60% September 30, 70% October 2, 80% October 5, 90% October 9. Observed first fall frost in recent years: 2022 October 16, 2023 September 22.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 13Sep 27Oct 92022: October 162023: September 22
Two charts, because spring and fall answer different questions: in spring, the chance that a frost still comes after a date; in fall, the chance that the first frost has already come before it. NOAA publishes these odds from 10% to 90%, so the lines stop there. ◆ marks the actual date in each recent year.

What actually happened in recent years

Observed dates of the last spring and first fall frost (32°F) at this station; ◆ marks them on the charts above
YearLast spring frostFirst fall frost
2021incomplete recordincomplete record
2022June 19October 16
2023May 8September 22
2024incomplete recordno data
2025incomplete recordno data
2026no dataseason not over yet

What these dates mean

The 131 days between the 50% dates in Imlay define the window when light frosts are equally likely to have occurred. The 50% light-frost date in spring is May 17, and the 50% light-frost date in fall is September 27; each marks a 50 % chance of a frost later (spring) or earlier (fall).

For a cautious planting plan, the spring date to set out tender crops is June 8, when there is only a 10 % chance of a frost later. In the autumn, the cautious date to finish harvesting tender crops is September 13, with only a 10 % chance that a frost has arrived earlier. By contrast, April 30 and October 9 carry a 90 % chance of a frost and represent gambles.

Hard frost at 28 °F is a greater threat than light frost at 32 °F because it can cause more severe injury; the 50% hard-frost dates are May 3 in spring and October 6 in fall.

How to read the probabilities

The dates are probabilities from 30 years of weather, not a forecast for this year.

  • Spring: "10% after June 8" means that in about one spring out of ten a frost still happens after that date. The 90% date is the earliest: a frost after it happens in most years.
  • Fall: "10% before September 13" means that in about one fall out of ten the first frost arrives before that date.
  • 50% is the typical date: half of the years are earlier, half are later.
  • A light frost (32°F) damages tender plants; a hard frost (28°F) also stops most hardy vegetables.

Nearby weather stations

Map of weather stations near Imlay, NVNumbered nearest stations: 1 — Winnemucca, NV — 25 mi; 2 — Lovelock, NV — 37 mi; 3 — Orovada, NV — 65 mi; 4 — Battle Mountain, NV — 67 mi; 5 — Beowawe, NV — 89 mi.NV25 mi · 40 km1. Winnemucca, NV — 25 mi12. Lovelock, NV — 37 mi23. Orovada, NV — 65 mi34. Battle Mountain, NV — 67 mi45. Beowawe, NV — 89 mi5
  1. Winnemucca, NV 25 mi (40 km)
  2. Lovelock, NV 37 mi (60 km)
  3. Orovada, NV 65 mi (105 km)
  4. Battle Mountain, NV 67 mi (107 km)
  5. Beowawe, NV 89 mi (143 km)

Sources

* Hardiness zone 6a: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.6564, -118.1631.