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Roof Coating Weather in Idaho: Best Months by City

Roof Coating season in Idaho, city by city: peak months, season boundaries, and annual workable-day counts from NOAA 1991–2020 normals. Coeur d'Alene leads with 127 workable days a year; Nampa runs the shortest at 91.

Across Idaho's 5 listed cities, annual workable days for roof coating run from 91 (Nampa) up to 127 (Coeur d'Alene). 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, September 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 Idaho

Peak months and season boundaries from NOAA 1991–2020 normals; season = months with at least 8 workable days.
CityPeak monthsSeasonWorkable days/yr
Boise Sep, Jun, May April–June 114
Nampa Sep, Jun, May May–June 91
Coeur d'Alene Aug, Jul, Sep May–September 127
Meridian Sep, Jun, May April–June 114
Idaho Falls Jul, Aug, Sep May–September 118

The rules behind these numbers

Typical label thresholds for roof coating — the single ruleset used by every check on this page.
CheckThresholdWhy 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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