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Second summer: the warm spell that follows the first autumn frost

October to November

Second summer is a stretch of abnormally warm weather in mid to late autumn that comes after the season's first frost. The American Meteorological Society now recommends that name; its glossary calls the older name, Indian summer, discouraged and disrespectful of Native American people.

Why this time of year

The season's first frost arrives in eastern Massachusetts in October in most years, and a warm spell can follow it. Once that frost hits, watch the forecast for a return to warm afternoons - that reversal from cold back to warm is the pattern itself.

How to notice it

  1. Note when the season's first real frost hits - frozen dew on the grass, or tender garden plants suddenly blackened and wilted.
  2. Watch the forecast in the days or weeks after that frost for a run of afternoons warm enough to feel like summer again, not just an average mild fall day.
  3. Check the order: the warmth has to come after the frost, not before it. A mild day before the first frost doesn't count as this pattern.

Try this with kids: First it got so cold outside that some plants turned brown or the grass got a white frost coating. Now the air feels warm again, almost like summer. Can you find the day it got cold, and then the day the warmth came back?

growing season: the part of the year warm enough for most plants to keep growing, ended by the first hard frost

Sources

  • glossary.ametsoc.orgAMS Glossary of Meteorology's current entry (the term 'Indian summer' now redirects here) defines the phenomenon as 'a period of abnormally warm weather that occurs in mid- to late autumn and after the first frost.'
  • glossary.ametsoc.orgAMS Glossary 'Indian summer' entry: the term is discouraged, 'considered a relic of the past and disrespectful of Native American people', with second summer as the replacement. (glossary.ametsoc.org 403s to curl; read in a browser 2026-09-22.)
  • essic.umd.eduUMD ESSIC scientist Phil Arkin: 'It's a period of warm weather that follows weather cold enough to stop the growing season,' timing varies by location based on local first-frost dates.
  • umass.eduUMass Extension Massachusetts freeze/frost occurrence table (NOAA climatography): median fall 32F dates at eastern stations run from Sep 29 (Taunton) to Oct 20 (Lawrence), Middleton Oct 11, Plymouth Oct 16; 28F medians Oct 11 to Nov 3.

Checked against these sources on September 22, 2026.

In the guide for October, November

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