Is it good to paint in Lowell, MA this week?
A live 7-day go/no-go calendar for exterior paint in Lowell, 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
- 2.7°F
- Overnight dew
- High
- Rain
- 7%
- Window
- —
High condensation risk overnight — surface dips to within 2.7°F of the 61°F dew point (low 62°F, 14% cloud, 5 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 3.7°F
- Overnight dew
- Watch
- Rain
- 26%
- Window
- —
Rain likely in the 24h cure window (26% chance, ~3.6mm) — it can wash out or mar an uncured paint.
- Dew margin
- -3°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within -3°F of the 47°F dew point (low 43°F, 5% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- -0.4°F
- Overnight dew
- High
- Rain
- 16%
- Window
- —
High condensation risk overnight — surface dips to within -0.4°F of the 52°F dew point (low 51°F, 100% cloud, 2 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 12.8°F
- Overnight dew
- Low
- Rain
- 15%
- Window
- 10am–5pm
Clear to paint: temps 54–67°F, RH under 85%, surface stays 12.8°F+ above the dew point, no rain in the cure window.
- Dew margin
- 13.2°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 11am–5pm
Cold mornings (down to 42°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
- Dew margin
- 13.8°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 2.7°F of the 61°F dew point (low 62°F, 14% cloud, 5 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- High humidity (95%, over the 85% mark) slows drying — keep an eye on the cure window.
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.