Is it good to paint in Boulder, CO this week?
A live 7-day go/no-go calendar for exterior paint in Boulder, 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
- 5.2°F
- Overnight dew
- Low
- Rain
- 4%
- Window
- 8am–5pm
Clear to paint: temps 56–73°F, RH under 49%, surface stays 5.2°F+ above the dew point, no rain in the cure window.
- Dew margin
- 25.2°F
- Overnight dew
- Low
- Rain
- 0%
- Window
- 9am–5pm
Cold mornings (down to 49°F, floor is 50°F) — wait for the surface to warm past midday before you paint.
- Dew margin
- 15°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Hot afternoon (86°F, ceiling 85°F) — paint early and follow the shade.
- Dew margin
- 23.9°F
- Overnight dew
- Low
- Rain
- 1%
- Window
- 8am–5pm
Clear to paint: temps 58–79°F, RH under 45%, surface stays 23.9°F+ above the dew point, no rain in the cure window.
- Dew margin
- 16.3°F
- Overnight dew
- Low
- Rain
- 3%
- Window
- —
Rain likely in the 24h cure window (3% chance, ~1.1mm) — it can wash out or mar an uncured paint.
- Dew margin
- 22.1°F
- Overnight dew
- Low
- Rain
- 10%
- Window
- 8am–5pm
Clear to paint: temps 65–83°F, RH under 43%, surface stays 22.1°F+ above the dew point, no rain in the cure window.
- Dew margin
- 38.1°F
- Overnight dew
- Low
- Rain
- 2%
- Window
- 8am–5pm
Clear to paint: temps 65–83°F, RH under 31%, surface stays 38.1°F+ above the dew point, no rain in the cure window.
- Clear to paint: temps 56–73°F, RH under 49%, surface stays 5.2°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
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.
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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.