Is it good to paint in Nashua, NH this week?
A live 7-day go/no-go calendar for exterior paint in Nashua, built from the local forecast against the 5°F-above-dew-point rule. We lead with the signal a weather app misses: overnight condensation risk.
- Dew margin
- 2.1°F
- Overnight dew
- High
- Rain
- 7%
- Window
- —
High condensation risk overnight — surface dips to within 2.1°F of the 62°F dew point (low 61°F, 14% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 5.6°F
- Overnight dew
- Low
- Rain
- 38%
- Window
- 9am–5pm
High humidity (90%, over the 85% mark) slows drying — keep an eye on the cure window.
- Dew margin
- -4°F
- Overnight dew
- High
- Rain
- 0%
- Window
- —
High condensation risk overnight — surface dips to within -4°F of the 45°F dew point (low 41°F, 8% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 0.2°F
- Overnight dew
- High
- Rain
- 22%
- Window
- —
High condensation risk overnight — surface dips to within 0.2°F of the 48°F dew point (low 47°F, 21% cloud, 1 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 11.1°F
- Overnight dew
- Low
- Rain
- 22%
- Window
- 9am–5pm
High humidity (91%, over the 85% mark) slows drying — keep an eye on the cure window.
- Dew margin
- 8.9°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 12pm–5pm
Cold mornings (down to 40°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
- Dew margin
- 13.1°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 10am–5pm
Cold mornings (down to 43°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
- High condensation risk overnight — surface dips to within 2.1°F of the 62°F dew point (low 61°F, 14% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Humidity peaks at 96% — well above the 85% ceiling; cure stalls and moisture gets trapped.
Hold off. These are forecast numbers — confirm the surface temperature on-site before you start.
Why these thresholds
Overnight dew condensing on a fresh coat causes blistering, surfactant leaching and peeling — the cause of 40%+ of exterior paint failures.
- • Surface temp must stay 5°F above the dew point through application and cure (ASTM D3276 / ISO 8502-42).
- • Air + surface in the 50–85°F band (low-temp lines to 35°F).
- • Humidity under 85%; ideally under 70%.
- • No rain for 24h after application.
- • We use the forecast ground-surface temperature as a surface-temp proxy — confirm on-site with an IR thermometer.
Free in the beta
Watch this job site 24/7
Get an email the moment overnight dew, rain, or an out-of-range stretch threatens a fresh coat — and a morning digest with the best window ahead. No app to check; we watch the forecast for you.