Is it good to paint in Madison, WI this week?
A live 7-day go/no-go calendar for exterior paint in Madison, 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
- -0.3°F
- Overnight dew
- High
- Rain
- 1%
- Window
- —
High condensation risk overnight — surface dips to within -0.3°F of the 56°F dew point (low 50°F, 0% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 2°F
- Overnight dew
- High
- Rain
- 36%
- Window
- —
High condensation risk overnight — surface dips to within 2°F of the 58°F dew point (low 59°F, 100% cloud, 8 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 1.1°F
- Overnight dew
- High
- Rain
- 72%
- Window
- —
High condensation risk overnight — surface dips to within 1.1°F of the 61°F dew point (low 61°F, 100% cloud, 11 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 8.2°F
- Overnight dew
- Low
- Rain
- 57%
- Window
- 3pm–5pm
High humidity (95%, over the 85% mark) slows drying — keep an eye on the cure window.
- Dew margin
- -11.3°F
- Overnight dew
- High
- Rain
- 23%
- Window
- —
High condensation risk overnight — surface dips to within -11.3°F of the 42°F dew point (low 31°F, 0% cloud, 5 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- -11.3°F
- Overnight dew
- High
- Rain
- 18%
- Window
- —
High condensation risk overnight — surface dips to within -11.3°F of the 53°F dew point (low 41°F, 100% cloud, 13 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- Dew margin
- 10.2°F
- Overnight dew
- Low
- Rain
- 11%
- Window
- 9am–5pm
Clear to paint: temps 54–63°F, RH under 77%, surface stays 10.2°F+ above the dew point, no rain in the cure window.
- High condensation risk overnight — surface dips to within -0.3°F of the 56°F dew point (low 50°F, 0% cloud, 4 mph wind). A fresh paint can blush/blister. Stop 4h before dew falls.
- High humidity (93%, 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.