Lake Oswego, Oregon Weather
Rufous Hummingbirds Arrive. Day 76 of spring. Read this microseason across nine climate regions →
Lake Oswego weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Light Rain20%0.08″71°54°—
- ThursdayJun 4Overcast——68°52°-3°
- FridayJun 5Overcast11%—64°47°-4°
- SaturdayJun 6Drizzle67%—63°46°-1°
- SundayJun 7Overcast——71°42°+8°
- MondayJun 8Light Drizzle45%0.15″56°48°-15°
- TuesdayJun 9Light Drizzle37%—62°48°+6°
PM2.5/PM10 ratio 0.67 with 5 mph wind — characteristic of long-range haze transport rather than a local source. AQI flat over the last 6 hours (within ±4 points).
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 45 now. With UV 6.5 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 28 by mid-afternoon.
- Present
- AQI 45
- UV peak
- 6.5 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 28
PM × Wind × Precip
PM2.5/PM10 ratio 0.67 with 5 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.67
- Wind
- light
- Recent rain
- 1h in last 6h
- Pattern
- transport
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 6:29 AM
- Moonset
- 2:53 PM
- In sign
- ♑︎ Capricorn
Rufous Hummingbirds Arrive
Lake Oswego at a glance
- Today vs. normal: 6°F below the seasonal normal for this latitude
- Last frost: May 18 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | — | — |
| May | lettuce, peas, spinach, radishes | lettuce, peas, radishes |
| June | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | tomatoes, peppers, beans, squash, fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | — | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Lake Oswego's warmest month is August (~70°F mean) and its coldest is December (~42°F). Rainfall peaks in December (7.3 inches) and bottoms out in July (0.4 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 42° | 6.4″ | 14 |
| February | 45° | 4.7″ | 10 |
| March | 48° | 4.8″ | 12 |
| April | 53° | 3.6″ | 11 |
| May | 59° | 2.6″ | 8 |
| June | 63° | 1.5″ | 5 |
| July | 69° | 0.4″ | 2 |
| August | 70° | 0.5″ | 2 |
| September | 65° | 1.6″ | 4 |
| October | 55° | 4.0″ | 9 |
| November | 47° | 6.6″ | 13 |
| December | 42° | 7.3″ | 14 |
Regional context
Lake Oswego sits within a warm-summer Mediterranean climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Portland, OR, Eugene, OR, Salem, OR, Medford, OR, Bend, OR.
Frequently asked
- When does it freeze in Lake Oswego?
- Lake Oswego's last spring frost typically falls around mid-May, and the first fall frost arrives around mid-October.
- What is the rainy season in Lake Oswego?
- December is the wettest month with about 7.3 inches of rain on average; the city receives roughly 44 inches annually.
- What is the warmest month in Lake Oswego?
- August is typically warmest, averaging about 70°F.
- What is the coldest month in Lake Oswego?
- December is typically coldest, averaging about 42°F.
- When can I start a vegetable garden in Lake Oswego?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-May); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Lake Oswego get?
- Lake Oswego averages about 102 rainy days per year.
- What hardiness zone is Lake Oswego?
- Lake Oswego's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Lake Oswego, Oregon sits in a warm-summer Mediterranean climate zone. January means hover near 42°F while July averages 69°F — a 27°F seasonal swing.
Across the year, Lake Oswego receives about 44 inches of precipitation spread over roughly 102 rainy days.
The rhythm of the year is set by latitude (45.4°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.