Is it good to stain in Chicago, IL this week?
A live 7-day go/no-go calendar for deck & fence stain in Chicago, 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
- 1.4°F
- Overnight dew
- High
- Rain
- 92%
- Window
- —
High condensation risk overnight — surface dips to within 1.4°F of the 63°F dew point (low 64°F, 100% cloud, 5 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 1.1°F
- Overnight dew
- High
- Rain
- 79%
- Window
- —
High condensation risk overnight — surface dips to within 1.1°F of the 66°F dew point (low 57°F, 100% cloud, 12 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Dew margin
- 8.5°F
- Overnight dew
- Low
- Rain
- 3%
- Window
- 8am–5pm
Clear to stain: temps 57–62°F, RH under 74%, surface stays 8.5°F+ above the dew point, no rain in the cure window.
- Dew margin
- 5.1°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to stain: temps 56–67°F, RH under 60%, surface stays 5.1°F+ above the dew point, no rain in the cure window.
- Dew margin
- 8.5°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to stain: temps 58–72°F, RH under 62%, surface stays 8.5°F+ above the dew point, no rain in the cure window.
- Dew margin
- 9.6°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 8am–5pm
Clear to stain: temps 55–58°F, RH under 49%, surface stays 9.6°F+ above the dew point, no rain in the cure window.
- Dew margin
- 24.4°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 9am–5pm
Cold mornings (down to 50°F, floor is 50°F) — wait for the surface to warm past midday before you stain.
- High condensation risk overnight — surface dips to within 1.4°F of the 63°F dew point (low 64°F, 100% cloud, 5 mph wind). A fresh stain can blush/blister. Stop 4h before dew falls.
- Humidity peaks at 98% — well above the 85% ceiling; cure stalls and moisture gets trapped.
- Rain likely in the 24h cure window (92% chance, ~2.5mm) — it can wash out or mar an uncured stain.
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.