Alaska weather and outdoor projects
Alaska’s outdoor season is short and varies enormously by region. Anchorage has cool summers and a moderate coastal climate, while Fairbanks in the Interior has warm, dry summer days and some of the coldest winters in the country. In much of the state, the window for paint, stain and concrete is roughly late May to early September.
Long summer daylight helps, because drying can continue into the evening, but cool nights still slow cure times. Late summer in Southcentral Alaska is often the rainiest part of the year, so June and early July are usually the best bet for staining and painting. Permafrost and frost heave affect slabs and footings in the Interior, and local building guidance for frost depth matters more than weather timing there.
Frost dates in Alaska
In Anchorage, the median last spring freeze (32°F) is around May 5 and the median first fall freeze is around October 1, a frost-free season of about 147 days.
In Fairbanks, the median last spring freeze (32°F) is around May 13 and the median first fall freeze is around September 13, a frost-free season of about 121 days.
Frost dates matter for concrete, which must not freeze in its first 48 hours, for paint and caulk that need nights above their minimum, and for lawn care, since crabgrass preventer goes down as the soil warms in spring. See how late in fall you can stain, paint or seal.
Best time to stain a deck in Alaska
In Anchorage, the most reliable months are June–August. May and September can also work on the right days. October–April is too cold, with average highs around 32°F. May and September are cool, with highs around 56°F, so choose the warmest afternoons.
In Fairbanks, the most reliable months are June–July. May and August can also work on the right days. October–April is too cold, with average highs around 19°F. In September, nights average about 36°F, too cold for the coating to dry and cure overnight. In May and August, nights average about 43°F, so finish early on mild days and check the overnight low.
Check this week’s hour-by-hour verdict with the deck staining forecast.
Best time to paint outside in Alaska
In Anchorage, the most reliable months are June–August. May and September can also work on the right days. October–April is too cold, with average highs around 32°F. May and September are cool, with highs around 56°F, so choose the warmest afternoons.
In Fairbanks, the most reliable months are June–August. May and September can also work on the right days. October–April is too cold, with average highs around 19°F. In May, nights average about 39°F, so finish early on mild days and check the overnight low. September is cool, with highs around 55°F, so choose the warmest afternoons.
Check this week’s hour-by-hour verdict with the exterior painting forecast.
Best time to pour concrete in Alaska
In Anchorage, the most reliable months are June–August. May and September can also work on the right days. October–April averages about 26 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. May and September bring about 3 freezing nights a month, so pick a mild spell and keep curing blankets on hand.
In Fairbanks, the most reliable months are June–August. May can also work on the right days. September–April averages about 27 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. May brings about 6 freezing nights a month, so pick a mild spell and keep curing blankets on hand.
Check this week’s hour-by-hour verdict with the concrete pouring forecast.
Best time to seal a driveway in Alaska
Anchorage has no month that is easy for this job on average; the best chances come in June–August. September–May is too cold, with average highs around 37°F. June–August is cool, with highs around 65°F, so choose the warmest afternoons.
In Fairbanks, the most reliable months are July. June and August can also work on the right days. September–April is too cold, with average highs around 24°F. In May, nights average about 39°F, too cold for the coating to dry and cure overnight. In June, nights average about 50°F, so finish early on mild days and check the overnight low. August is cool, with highs around 66°F, so choose the warmest afternoons.
Check this week’s hour-by-hour verdict with the driveway sealing forecast.
Best time to fertilize or treat a lawn in Alaska
In Anchorage, the most reliable months are June–August. May and September can also work on the right days. October–April is too cold, with average highs around 32°F. May and September are cool, with highs around 56°F, so choose the warmest afternoons.
In Fairbanks, the most reliable months are May–August. September can also work on the right days. October–April is too cold, with average highs around 19°F. September is cool, with highs around 55°F, so choose the warmest afternoons.
Check this week’s hour-by-hour verdict with the lawn fertilizer forecast.
How the weather differs across Alaska
| Place | Hottest month avg high | Coldest month avg low | Rain per year | Last spring freeze | First fall freeze |
|---|---|---|---|---|---|
| Anchorage | 66°F | 11°F | 16 in | May 5 | October 1 |
| Fairbanks | 73°F | -17°F | 12 in | May 13 | September 13 |
Of the places above, Anchorage has the most good months for staining, painting and concrete combined (9 job-months), and Fairbanks has the fewest (8). If you live between them, expect something in between, and higher ground to be cooler with a shorter season.
Monthly weather in Anchorage
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 23°F | 11°F | 3 | 0.8 in | 74% | 30 |
| February | 27°F | 15°F | 3 | 0.9 in | 68% | 27 |
| March | 33°F | 19°F | 2 | 0.7 in | 55% | 29 |
| April | 45°F | 30°F | 1 | 0.4 in | 51% | 19 |
| May | 56°F | 40°F | 2 | 0.7 in | 48% | 3 |
| June | 63°F | 48°F | 3 | 1.0 in | 55% | 0 |
| July | 66°F | 53°F | 5 | 1.8 in | 62% | 0 |
| August | 64°F | 51°F | 8 | 2.9 in | 64% | 0 |
| September | 56°F | 43°F | 8 | 3.1 in | 63% | 3 |
| October | 42°F | 31°F | 5 | 1.8 in | 65% | 18 |
| November | 29°F | 18°F | 4 | 1.2 in | 72% | 27 |
| December | 25°F | 14°F | 4 | 1.2 in | 77% | 31 |
*Days with at least 0.1 inch of rain or melted snow. Freezing nights: average nights a month at or below 32°F. Humidity is calculated from NOAA hourly normal temperature and dew point at 3 PM.
Monthly weather in Fairbanks
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 1°F | -17°F | 2 | 0.6 in | 93% | 31 |
| February | 12°F | -11°F | 2 | 0.5 in | 73% | 28 |
| March | 25°F | -3°F | 1 | 0.4 in | 49% | 31 |
| April | 46°F | 22°F | 1 | 0.3 in | 38% | 26 |
| May | 62°F | 39°F | 2 | 0.5 in | 32% | 6 |
| June | 72°F | 50°F | 5 | 1.5 in | 39% | 0 |
| July | 73°F | 53°F | 6 | 2.3 in | 47% | 0 |
| August | 66°F | 48°F | 6 | 2.1 in | 52% | 0 |
| September | 55°F | 36°F | 4 | 1.4 in | 52% | 9 |
| October | 34°F | 18°F | 3 | 0.8 in | 65% | 29 |
| November | 12°F | -4°F | 2 | 0.7 in | 80% | 30 |
| December | 4°F | -13°F | 2 | 0.6 in | 86% | 31 |
Use the averages, then check the forecast
These ratings describe a typical month, not a particular week. A warm spell in a “poor” month can give you a good day, and a wet week can spoil a “good” one. Use this page to plan the season, then check the 7-day forecast for your ZIP code before you buy materials or book help. Each project forecast checks the hours after you finish too: overnight lows, dew and rain that would ruin fresh stain, paint, sealer or concrete.
About this data
Monthly temperatures, rain days, snowfall and freeze dates are NOAA National Centers for Environmental Information (NCEI) U.S. Climate Normals for 1991–2020 at ANCHORAGE INTL AP, FAIRBANKS INTL AP. Ratings apply the same temperature limits as our forecasts (for example, 50°F or warmer for deck stain and driveway sealer, and no freezing nights for new concrete) to the average month. Your product label always takes priority.
Frequently asked questions
When is the best time to stain a deck in Alaska?
In Anchorage, June–August. In Fairbanks, June–July. Look for at least 24 dry hours before and after, and nights above about 40°F. The deck staining forecast checks your exact week.
When is the last frost in Alaska?
Anchorage: around May 5; Fairbanks: around May 13. These are median dates from NOAA 1991–2020 normals, so a freeze after them happens in about half of years. Low spots and valleys freeze later in spring.
Can you pour concrete in winter in Alaska?
Yes, but it needs cold-weather practices. Anchorage averages about 88 freezing nights from December to February, so fresh concrete needs insulated blankets, a heated enclosure or an accelerated mix, and must not freeze in the first 48 hours. Many homeowners wait for spring.
What months are best for sealing a driveway in Alaska?
In Anchorage, conditions are marginal in most months, so choose warm, dry spells. In Fairbanks, July. Most sealers need 50°F or warmer for 24 hours and a dry day after. See the driveway sealing forecast.