U.S. Frost Dates by Weather Station

NOAA station USC00275712 · New Hampshire

Frost Dates for Nashua, NH

NOAA weather station Nashua 2 NNW (USC00275712), New Hampshire · elevation 135 ft (41 m) · hardiness zone 6a*

  • Lower-risk planting dateafter May 11only 1 spring in 10 still has a frost later
  • Typical last frostApril 3050% chance of a frost after it
  • Typical first fall frostOctober 1250% chance of a frost before it
  • Frost-free season165 daystypical year, 32°F
  • Hardiness zone6acalculated*

The year at a glance

Frost season at Nashua, NHSpring: a frost after April 18 in 9 years out of 10, after April 30 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 12 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 165 days.JanFebMarAprMayJunJulAugSepOctNovDecLast frost ~Apr 30First frost ~Oct 12Frost season at Nashua, NHSpring: a frost after April 18 in 9 years out of 10, after April 30 in half of the years, after May 11 in 1 year out of 10. Fall: the first frost comes before September 30 in 1 year out of 10, before October 12 in half of the years, before October 28 in 9 years out of 10. Typical frost-free season: 165 days.JFMAMJJASONDLast frost ~Apr 30First frost ~Oct 12
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)May 11September 30
50% (typical)April 30October 12
90% (likely)April 18October 28
Frost-free season (32°F, 50% chance)
165 days
Hard frost (28°F), last in spring, 50% chance after
April 17
Hard frost (28°F), first in fall, 50% chance before
October 24

The last 15 years (2006–2020 normals)

Typical last frost April 27 (3 days earlier than the 30-year normal), typical first fall frost October 20 (8 days later). Frost-free season 174 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 Nashua: chance of a frost after this dateSpring, chance of a frost after the date: 10% May 11, 20% May 6, 30% May 4, 40% May 1, 50% April 30, 60% April 27, 70% April 24, 80% April 22, 90% April 18. Observed last spring frost in recent years: 2021 April 22, 2022 April 21, 2023 May 18, 2024 April 27, 2025 April 19, 2026 April 25.Spring: last frostChance of a frost after this date10%50%90%May 1May 11Apr 30Apr 182021: April 222022: April 212023: May 182024: April 272025: April 192026: April 25Fall at Nashua: chance of a frost before this dateFall, chance of a frost before the date: 10% September 30, 20% October 2, 30% October 5, 40% October 8, 50% October 12, 60% October 15, 70% October 18, 80% October 22, 90% October 28. Observed first fall frost in recent years: 2021 October 29, 2022 October 20, 2023 October 31, 2024 October 17, 2025 October 10.Fall: first frostChance of a frost before this date10%50%90%Oct 1Nov 1Sep 30Oct 12Oct 282021: October 292022: October 202023: October 312024: October 172025: October 10
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
2021April 22October 29
2022April 21October 20
2023May 18October 31
2024April 27October 17
2025April 19October 10
2026April 25season not over yet

What these dates mean

The 165-day span between the 32 °F 50% dates in Nashua frames the period when a light frost is less than even odds, marking the core growing window. The 50% date in spring is April 30, indicating an even chance of a light frost later, while the fall 50% date is October 12, indicating an even chance of a light frost earlier.

For tender crops, the cautious spring date is May 11, which carries only a 10 % chance of a light frost later, so planting after this date keeps risk low. In the autumn, the cautious date to finish harvesting tender crops is September 30, with only a 10 % chance that a light frost has arrived earlier.

A hard frost at 28 °F, noted by the median dates April 17 in spring and October 24 in fall, can damage plants that would survive a 32 °F light frost, making those temperatures a stricter limit for gardeners.

How to read the probabilities

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

  • Spring: "10% after May 11" 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 30" 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 Nashua, NHNumbered nearest stations: 1 — Lowell, MA — 12 mi; 2 — near Manchester, NH — 14 mi; 3 — Lawrence, MA — 17 mi; 4 — Haverhill, MA — 21 mi; 5 — Groveland, MA — 22 mi.MANHVTME25 mi · 40 km1. Lowell, MA — 12 mi12. near Manchester, NH — 14 mi23. Lawrence, MA — 17 mi34. Haverhill, MA — 21 mi45. Groveland, MA — 22 mi5
  1. Lowell, MA 12 mi (19 km)
  2. near Manchester, NH 14 mi (23 km)
  3. Lawrence, MA 17 mi (27 km)
  4. Haverhill, MA 21 mi (34 km)
  5. Groveland, MA 22 mi (36 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: 42.7914, -71.4736.