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.
How New Hampshire compares with other states
Concord has the 3rd-shortest frost-free season of the 50 state main stations (146 days). Concord has the 4th-most freezing nights of the 50 state main stations (165 a year). Concord is tied for the 10th-most rainy days of the 50 state main stations (80 a year with 0.1 in or more).
| Measure (Concord) | Value | Rank, highest first |
|---|---|---|
| Deck staining season | 4 good months | 20th of 50 |
| Frost-free season | 146 days | 48th of 50 |
| Freezing nights | 165 a year | 4th of 50 |
| Rainy days | 80 a year with 0.1 in or more | 10th of 50 |
| Days at 90°F or hotter | 14 a year | 40th of 50 |
| Summer afternoons | 48% humidity at 3 PM, June–August | 31st of 47 |
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 (average highs May 69°F). 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.
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 (average highs Apr 58°F, May 69°F, Oct 61°F). 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.
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 (average highs May 69°F). 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.
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 (average highs May 69°F, Sep 74°F). 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.
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 (average highs Apr 58°F). November–March is too cold, with average highs around 39°F. April is cool, with highs around 58°F, so choose the warmest afternoons.
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 0.1 inch of rain or more; column notes.
Source: NOAA NCEI U.S. Climate Normals 1991–2020 for CONCORD MUNI AP. See how the ratings work and how late in fall you can stain, paint or seal.
Frequently asked questions
When is the best time to stain a deck in New Hampshire?
In Concord, June–September.
When is the last frost in New Hampshire?
Concord: around May 8.
Can you pour concrete in winter in New Hampshire?
Yes, with 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.