Frost dates for Bangor, Maine
In Bangor, half of springs have had their last frost by May 4 (and 1 spring in 10 still has one after May 17), and half of falls have had their first frost by October 4, leaving about 152 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Bangor, Maine
Last spring frost
May 4
Half of springs have their last frost by this date. For a safer bet, wait until May 17: only 1 spring in 10 has a frost after that.
First fall frost
October 4
Half of falls have their first frost by this date. In 1 fall in 10 it comes by September 23.
Growing season
152 days
Frost-free days in a typical year. 9 years in 10 get at least 134.
Hardiness zone
5a
2023 USDA map: the coldest night of winter averages −20°F to −15°F. It was 5a on the 2012 map too. All 3 ZIP codes within about 6 miles of the city's center are in zone 5a.
Print a year planner for Bangor
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | April 24 | May 4 | May 17 |
| First frost in fall | September 23 | October 4 | October 21 |
The frost-free season between them runs 152 days in a typical year. In 1 year in 10 it is 170 days or longer, and in 1 year in 10 it is 134 days or shorter.
- Hard freeze (28°F): typically last on April 23 and first on October 17. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on May 17 and first on September 25. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Bangor comes between April 24 and May 17, a window of 23 days. That is narrower than at most NOAA stations (the typical window is 31 days), so the typical date is a steadier guide here than in most places.
Among Maine's 82 NOAA stations with a frost every year, 70 percent have their typical last frost later than Bangor does.
Planting calendar for Bangor
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
Your season is too short for a separate fall planting of cabbage: sown late enough to be a fall crop, it wouldn't be ready before the typical first frost. Your spring planting is your harvest.
| When | What to do | Why then |
|---|---|---|
| February | ||
| February 16 to March 16 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| March | ||
| March 2 to 30 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| March 16 to April 6 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| March 23 to April 6 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| March 30 to April 13 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| April | ||
| April 6 to 20 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April 6 to 20 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April 20 to May 4 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| April 20 to May 4 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| May | ||
| May 4 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| May 18 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| May 18 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| May 29 to June 12 | Broccoli for fall Start seeds | set the plants out by July 17 |
| July | ||
| July 8 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July 12 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| July 13 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July 17 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| July 18 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| July 22 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| August | ||
| August 1 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| August 11 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| August 21 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 23 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| October | ||
| October 24 to 31 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
Want more insurance? Shift every spring date 13 days later. That plans around May 17, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Bangor International Airport (station USW00014606), 3 miles from the center of Bangor. It sits at about the same elevation, 150 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
Our ZIP code lookup matches these 14 ZIP codes to the same station, so they get the same dates: 04401, 04412, 04416, 04419, 04429, 04431, 04438, 04444, 04450, 04456, 04472, 04474, 04496, 04951. Hardiness zones are worked out separately for each ZIP code.
The nearest other places with pages
- Lewiston, Maine: last frost around April 25, first frost around October 19 (85 miles away)
- Portland, Maine: last frost around April 26, first frost around October 15 (110 miles away)
See frost dates across Maine, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.