Roof Coating Weather in Indiana: Best Months by City
Roof Coating season in Indiana, city by city: peak months, season boundaries, and annual workable-day counts from NOAA 1991–2020 normals. Evansville leads with 171 workable days a year; South Bend runs the shortest at 117.
Across Indiana's 12 listed cities, annual workable days for roof coating run from 117 (South Bend) up to 171 (Evansville). Every number comes from NOAA 1991–2020 normals scored against the same label ruleset; every city name links to its live 10-day check.
Statewide, August is the strongest month — it tops or ties the table in most listed cities. The live strips on each city page decide the week; this table decides the month. Scoring rules: methodology; the national playbook: the roof coating guide.
Cities in Indiana
| City | Peak months | Season | Workable days/yr |
|---|---|---|---|
| Indianapolis | Aug, Sep, Jul | April–October | 131 |
| Fort Wayne | Aug, Sep, Jul | May–October | 124 |
| South Bend | Aug, Jul, Sep | May–October | 117 |
| Evansville | Aug, Sep, Oct | April–November | 171 |
| Lafayette | Sep, Aug, Jul | April–October | 123 |
| Elkhart | Aug, Jul, Sep | May–October | 124 |
| Bloomington | Aug, Sep, Jul | April–October | 137 |
| Fishers | Sep, Aug, Jul | April–October | 129 |
| Carmel | Sep, Aug, Jul | April–October | 129 |
| Muncie | Oct, Aug, Sep | April–October | 131 |
| Anderson | Aug, Sep, Jul | April–October | 137 |
| Terre Haute | Sep, Aug, Jul | April–October | 130 |
The rules behind these numbers
| Check | Threshold | Why it matters |
|---|---|---|
| Air temperature | 50–90°F | Acrylic and elastomeric coatings want 50°F+ during application and initial cure. |
| Overnight low | ≥40°F during the first 24 h | Water-based coatings can be ruined by a cold, damp night before they skin over. |
| Dry before | ≤0.05" rain in the prior 24 h; watch back to 48 h | The membrane must be dry — coatings trap moisture that later blisters. |
| Dry after | <0.05" rain for 24 h after (48 h thick coats want 48 h) | Rain inside 24 hours washes uncured coating into gutters. |
| Evening dew-point spread | ≥5°F from 6–11 pm | Roofs radiate heat at night and hit the dew point before anything else in the yard. |
| Daytime humidity | ≤85% | Humid air slows water-based coatings dramatically. |
| Wind | ≤15 mph (roller only, no spray up to 20 mph) | Wind on a roof is a safety limit first and an overspray limit second. |
Always follow your product label — formulas vary. The table above is the typical range across major manufacturers, not a promise about your can.
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Other tasks in Indiana
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- Exterior Painting in Indiana
- Driveway Sealing in Indiana
- Concrete Pouring in Indiana
- Lawn Seeding in Indiana