Lawn Seeding Weather in Oregon: Best Months by City
Lawn Seeding season in Oregon, city by city: peak months, season boundaries, and annual workable-day counts from NOAA 1991–2020 normals. Beaverton leads with 318 workable days a year; Bend runs the shortest at 135.
Oregon is not one climate: Beaverton banks 318 workable lawn seeding days a year while Bend gets 135 — a spread the table below itemizes month by month. Season boundaries mark the first and last month averaging 8+ workable days against the label rules (50–85°F, nights 32°F+).
Statewide, May 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 lawn seeding guide.
Cities in Oregon
| City | Peak months | Season | Workable days/yr |
|---|---|---|---|
| Portland | Mar, May, Jul | February–November | 286 |
| Eugene | Mar, May, Oct | February–November | 258 |
| Salem | Mar, May, Oct | February–November | 288 |
| Medford | Mar, May, Oct | March–June | 192 |
| Bend | Jun, Sep, May | May–October | 135 |
| Gresham | Mar, May, Jul | February–November | 287 |
| Hillsboro | May, Jul, Aug | March–November | 266 |
| Beaverton | Mar, May, Jul | January–November | 318 |
The rules behind these numbers
| Check | Threshold | Why it matters |
|---|---|---|
| Air temperature | 50–85°F (low-temp formulas from 55°F) | Cool-season grasses germinate best with daytime highs of roughly 60–80°F. |
| Overnight low | ≥32°F during the first 48 h (≥40°F preferred) | Seed survives a light frost, but sustained cold stalls germination. |
| Dry before | no soaking (≥1.0") in the prior 24 h | Seeding into mud makes ruts and washes seed into low spots. |
| Dry after | <0.5" rain for 24 h after | Light rain after seeding helps. A 0.5"+ downpour washes seed out. |
| Wind | ≤15 mph (broadcast seed drifts up to 25 mph) | Broadcast spreading above 15 mph lands seed everywhere but the lawn. |
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 Oregon
- Deck Staining in Oregon
- Exterior Painting in Oregon
- Driveway Sealing in Oregon
- Concrete Pouring in Oregon
- Roof Coating in Oregon