ZIP 04108 Zone 6a

Maine · USDA zone 6a, average annual extreme minimum -10°F to -5°F.

Nearest qualified station: PORTLAND INTL JETPORT, ME US (USW00014764), 5.7 miles from the Census ZCTA internal point for this ZIP.

Median last 32°F is April 26. Median first 32°F is October 15. The 50% growing-season length is 170 days. The green band runs from the median last frost to the median first frost. Thin ticks mark the 10%, 50%, and 90% dates.

Outside the median season Growing seasonTicks: 10%, 50%, and 90%

Last 32°F in spring

NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.

ProbabilityDateHow to read it
90%April 16Earlier date. A last 32°F on or after this day is common.
50%April 26Median.
10%May 7Later date. A last 32°F on or after this day is uncommon.

First 32°F in fall

NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.

ProbabilityDateHow to read it
10%October 2Earlier date. A first 32°F on or before this day is uncommon.
50%October 15Median.
90%October 30Later date. A first 32°F on or before this day is common.

32°F growing-season length

Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.

Probability the season is at least this longDays
10%188
50%170
90%153

28°F threshold

10%50%90%
Last, on or afterApril 25April 14April 3
First, on or beforeOctober 14October 27November 9
Season at least212 days195 days177 days

36°F threshold

10%50%90%
Last, on or afterMay 20May 7April 28
First, on or beforeSeptember 24October 4October 17
Season at least164 days149 days132 days

Station PORTLAND INTL JETPORT, ME US (USW00014764). Completeness flag S, 30 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 13.7 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.

Methodology · Maine cities