New Hampshire weather and outdoor projects
New Hampshire has cold, snowy winters and warm summers, with a project season of roughly late May to late September. Concord and the southern part of the state are milder, while the White Mountains and the north have a shorter season and earlier frost.
Many homes have wood siding that needs regular painting or staining, and the best weather is usually from late June through early September, when nights stay warm enough. Fall foliage season brings cool nights that slow drying. New concrete needs good curing before long winters with frequent freeze-thaw cycles.
Frost dates in New Hampshire
In Concord, the median last spring freeze (32°F) is around May 8 and the median first fall freeze is around October 3, a frost-free season of about 146 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 New Hampshire
In Concord, the most reliable months are June–September. May can also work on the right days. November–March is too cold, with average highs around 39°F. In April and October, nights average about 36°F, too cold for the coating to dry and cure overnight. In May, nights average about 44°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 New Hampshire
In Concord, the most reliable months are June–September. April–May and October can also work on the right days. November–March is too cold, with average highs around 39°F. April is cool, with highs around 58°F, so choose the warmest afternoons. In May and October, nights average about 41°F, so finish early on mild days and check the overnight low.
Check this week’s hour-by-hour verdict with the exterior painting forecast.
Best time to pour concrete in New Hampshire
In Concord, the most reliable months are June–September. May can also work on the right days. October–April averages about 23 nights a month at or below 32°F, so fresh concrete needs blankets or heated enclosures. May brings about 3 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 New Hampshire
In Concord, the most reliable months are June–August. May and September can also work on the right days. November–April is too cold, with average highs around 42°F. In October, nights average about 38°F, too cold for the coating to dry and cure overnight. In May and September, nights average about 47°F, so finish early on mild days and check the overnight low.
Check this week’s hour-by-hour verdict with the driveway sealing forecast.
Best time to fertilize or treat a lawn in New Hampshire
In Concord, the most reliable months are May–October. April can also work on the right days. November–March is too cold, with average highs around 39°F. April is cool, with highs around 58°F, so choose the warmest afternoons.
Check this week’s hour-by-hour verdict with the lawn fertilizer forecast.
Monthly weather in Concord
| Month | Avg high | Avg low | Wet days* | Rain | 3 PM humidity | Freezing nights |
|---|---|---|---|---|---|---|
| January | 32°F | 13°F | 6 | 2.8 in | 54% | 30 |
| February | 35°F | 15°F | 6 | 2.8 in | 47% | 27 |
| March | 44°F | 23°F | 7 | 3.3 in | 44% | 27 |
| April | 58°F | 33°F | 7 | 3.4 in | 36% | 16 |
| May | 69°F | 44°F | 7 | 3.5 in | 40% | 3 |
| June | 78°F | 54°F | 7 | 3.8 in | 47% | 0 |
| July | 83°F | 59°F | 6 | 3.6 in | 48% | 0 |
| August | 82°F | 57°F | 6 | 3.6 in | 48% | 0 |
| September | 74°F | 49°F | 6 | 3.6 in | 49% | 1 |
| October | 61°F | 38°F | 7 | 4.4 in | 49% | 11 |
| November | 48°F | 29°F | 6 | 3.4 in | 51% | 21 |
| December | 37°F | 20°F | 7 | 3.7 in | 57% | 28 |
*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.
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 CONCORD MUNI 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 New Hampshire?
In Concord, June–September. 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 New Hampshire?
Concord: around May 8. 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 New Hampshire?
Yes, but it needs cold-weather practices. Concord averages about 85 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 New Hampshire?
In Concord, June–August. Most sealers need 50°F or warmer for 24 hours and a dry day after. See the driveway sealing forecast.