Is it good to stain in Portland, OR this week?
A live 7-day go/no-go calendar for deck & fence stain in Portland, 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
- 5.1°F
- Overnight dew
- Low
- Rain
- 15%
- Window
- 9am–5pm
Clear to stain: temps 57–65°F, RH under 84%, surface stays 5.1°F+ above the dew point, no rain in the cure window.
- Dew margin
- 4.6°F
- Overnight dew
- High
- Rain
- 4%
- Window
- —
High condensation risk overnight — surface dips to within 4.6°F of the 46°F dew point (low 51°F, 3% cloud, 4 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 5.4°F
- Overnight dew
- Low
- Rain
- 3%
- Window
- 8am–5pm
Clear to stain: temps 57–73°F, RH under 78%, surface stays 5.4°F+ above the dew point, no rain in the cure window.
- Dew margin
- 2.4°F
- Overnight dew
- High
- Rain
- 2%
- Window
- —
High condensation risk overnight — surface dips to within 2.4°F of the 47°F dew point (low 49°F, 0% cloud, 1 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 4.8°F
- Overnight dew
- Watch
- Rain
- 4%
- Window
- 8am–5pm
Watch overnight dew — surface comes within 4.8°F of the dew point (margin is 5°F). Time the coat to dry well before evening.
- Dew margin
- -0.2°F
- Overnight dew
- High
- Rain
- 1%
- Window
- —
High condensation risk overnight — surface dips to within -0.2°F of the 52°F dew point (low 52°F, 2% cloud, 2 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 18.1°F
- Overnight dew
- Low
- Rain
- 2%
- Window
- 8am–5pm
Clear to stain: temps 61–86°F, RH under 71%, surface stays 18.1°F+ above the dew point, no rain in the cure window.
- Clear to stain: temps 57–65°F, RH under 84%, surface stays 5.1°F+ above the dew point, no rain in the cure window.
Good to go. 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.
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.