U.S. Frost Dates by Weather Station

NOAA station USC00267123 · Nevada

Frost Dates for Ruby Lake NWR, NV

NOAA weather station Ruby Lake NWR (USC00267123), Nevada · elevation 6019 ft (1835 m) · hardiness zone 5b*

  • Lower-risk planting dateafter June 12only 1 spring in 10 still has a frost later
  • Typical last frostMay 2750% chance of a frost after it
  • Typical first fall frostSeptember 2350% chance of a frost before it
  • Frost-free season120 daystypical year, 32°F
  • Hardiness zone5bcalculated*

The year at a glance

Frost season at Ruby Lake NWR, NVSpring: a frost after May 5 in 9 years out of 10, after May 27 in half of the years, after June 12 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 120 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~May 27First frost ~Sep 23Frost season at Ruby Lake NWR, NVSpring: a frost after May 5 in 9 years out of 10, after May 27 in half of the years, after June 12 in 1 year out of 10. Fall: the first frost comes before September 10 in 1 year out of 10, before September 23 in half of the years, before October 4 in 9 years out of 10. Typical frost-free season: 120 days.JFMAMJJASONDLast frost ~May 27First frost ~Sep 23
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 26 years of NOAA records (1991–2020 normals)
ChanceLast frost in spring afterFirst frost in fall before
10% (unlikely)June 12September 10
50% (typical)May 27September 23
90% (likely)May 5October 4
Frost-free season (32°F, 50% chance)
120 days
Hard frost (28°F), last in spring, 50% chance after
May 7
Hard frost (28°F), first in fall, 50% chance before
October 2

The last 15 years (2006–2020 normals)

Typical last frost May 27 (same as the 30-year normal), typical first fall frost September 24 (1 day later). Frost-free season 119 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 Ruby Lake NWR: chance of a frost after this dateSpring, chance of a frost after the date: 10% June 12, 20% June 6, 30% June 3, 40% May 31, 50% May 27, 60% May 21, 70% May 16, 80% May 12, 90% May 5. Observed last spring frost in recent years: 2021 June 11, 2022 June 15, 2023 May 11.Spring: last frostChance of a frost after this date10%50%90%May 1Jun 1Jun 12May 27May 52021: June 112022: June 152023: May 11Fall at Ruby Lake NWR: chance of a frost before this dateFall, chance of a frost before the date: 10% September 10, 20% September 14, 30% September 18, 40% September 20, 50% September 23, 60% September 25, 70% September 28, 80% October 1, 90% October 4. Observed first fall frost in recent years: 2021 September 20, 2022 September 23, 2023 September 23.Fall: first frostChance of a frost before this date10%50%90%Sep 1Oct 1Sep 10Sep 23Oct 42021: September 202022: September 232023: September 23
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
2021June 11September 20
2022June 15September 23
2023May 11September 23
2024no datano data
2025no datano data
2026no dataseason not over yet

What these dates mean

Setting out tender crops on May 5 at Ruby Lake NWR is a gamble because there is a 90 % chance of a frost later than that date. The cautious spring date for tender crops is June 12, when only a 10 % chance of a later frost remains. The 50 % date in spring is May 27, indicating an even-odds point for a light frost, and the hard-frost 50 % date is May 7.

In the fall, the cautious date to finish harvesting tender crops is September 10, with a 10 % chance that a frost has already begun; the 50 % point for a light frost is September 23, while the hard-frost 50 % date is October 2. For a gardener, the 50 % dates mark the median moment when a light frost is equally likely to have occurred or not, giving a clear reference for risk assessment. A hard frost at 28 °F can damage plants that would survive a 32 °F light frost, so it represents a higher threat level.

How to read the probabilities

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

  • Spring: "10% after June 12" 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 10" 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 Ruby Lake NWR, NVNumbered nearest stations: 1 — Elko, NV — 46 mi; 2 — Lages, NV — 47 mi; 3 — Eureka, NV — 53 mi; 4 — Beowawe, NV — 58 mi; 5 — Beowawe 49 S - University of N Ranch, NV — 62 mi.25 mi · 40 km1. Elko, NV — 46 mi12. Lages, NV — 47 mi23. Eureka, NV — 53 mi34. Beowawe, NV — 58 mi45. Beowawe 49 S - University of N Ranch, NV — 62 mi5
  1. Elko, NV 46 mi (74 km)
  2. Lages, NV 47 mi (76 km)
  3. Eureka, NV 53 mi (86 km)
  4. Beowawe, NV 58 mi (94 km)
  5. Beowawe 49 S - University of N Ranch, NV 62 mi (99 km)

Sources

* Hardiness zone 5b: zone derived from PRISM 2023 grid at the station location (not the official USDA map). Source data: PRISM Group, Oregon State University.

Station coordinates: 40.2022, -115.493.