Is it good to stain in Lowell, MA this week?
A live 7-day go/no-go calendar for deck & fence stain 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
- 1.5°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within 1.5°F of the 59°F dew point (low 61°F, 2% cloud, 3 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 3.7°F
- Overnight dew
- High
- Rain
- 13%
- Window
- —
High condensation risk overnight — surface dips to within 3.7°F of the 62°F dew point (low 64°F, 0% cloud, 3 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 5.9°F
- Overnight dew
- Low
- Rain
- 28%
- Window
- 8am–5pm
Clear to stain: temps 71–88°F, RH under 75%, surface stays 5.9°F+ above the dew point, no rain in the cure window.
- Dew margin
- 4.2°F
- Overnight dew
- High
- Rain
- 26%
- Window
- —
High condensation risk overnight — surface dips to within 4.2°F of the 58°F dew point (low 56°F, 6% cloud, 5 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 7.4°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to stain: temps 63–78°F, RH under 59%, surface stays 7.4°F+ above the dew point, no rain in the cure window.
- Dew margin
- 0°F
- Overnight dew
- High
- Rain
- 53%
- Window
- —
High condensation risk overnight — surface dips to within 0°F of the 66°F dew point (low 61°F, 100% cloud, 6 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 6.8°F
- Overnight dew
- Low
- Rain
- 53%
- Window
- —
Humidity peaks at 99% — well above the 85% ceiling; cure stalls and moisture gets trapped.
- High condensation risk overnight — surface dips to within 1.5°F of the 59°F dew point (low 61°F, 2% cloud, 3 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
Hold off. These are forecast numbers — confirm the surface temperature on-site before you start.
Why these thresholds
Stain applied to a damp or dew-wet board can't penetrate — it beads, stays tacky and flakes. Wood must be dry and stay above the dew point while it sets.
- • Surface temp must stay 5°F above the dew point through application and cure (ASTM D3276 / ISO 8502-42).
- • Air + surface in the 50–90°F band (low-temp lines to 45°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.
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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.