Foster Dam, Oregon climate: Climate normals at a NOAA weather station
Foster Dam's normal year runs from 34°F December nights to 82°F July afternoons, with 54.5 inches of precipitation and less than an inch of snow (0.1 in) a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.3°C, December lows of 1°C, July highs of 28°C, 1,383 mm of precipitation a year.
- NOAA stationFoster Dam
- Station IDUSC00353047
- Location44.41°N 122.67°W
- Elevation550 ft (168 m)
On October 23, the normal high in Foster Dam is 61°F and the normal low 41°F, and the chance of measurable rain or snow is 46%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Foster Dam.
- Jan 48° 34°
- Feb 51° 35°
- Mar 56° 37°
- Apr 60° 40°
- May 67° 44°
- Jun 73° 48°
- Jul 82° 51°
- Aug 83° 50°
- Sep 76° 47°
- Oct 64° 42°
- Nov 53° 38°
- Dec 47° 34°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Foster Dam each month?
July is the warmest month, with normal highs of 82°F; December the coldest, with normal lows of 34°F. The most precipitation falls in December (8.40 in), the least in July (0.54 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 48°F | 34°F | 40.9°F | 7.15 | 19 | <1 | 13 | 9 h 10 min |
| February | 51°F | 35°F | 42.8°F | 5.56 | 17 | <1 | 11 | 10 h 30 min |
| March | 56°F | 37°F | 46.2°F | 6.26 | 19 | <1 | 7 | 11 h 50 min |
| April | 60°F | 40°F | 49.9°F | 5.37 | 18 | <1 | 2 | 13 h 20 min |
| May | 67°F | 44°F | 55.5°F | 3.80 | 13 | <1 | 1 | 14 h 50 min |
| June | 73°F | 48°F | 60.4°F | 2.46 | 9 | 1 | <1 | 15 h 30 min |
| July | 82°F | 51°F | 66.4°F | 0.54 | 3 | 6 | <1 | 15 h 10 min |
| August | 83°F | 50°F | 66.4°F | 0.64 | 3 | 7 | <1 | 14 h 10 min |
| September | 76°F | 47°F | 61.6°F | 1.99 | 7 | 2 | <1 | 12 h 40 min |
| October | 64°F | 42°F | 53.0°F | 4.64 | 13 | <1 | 2 | 11 h |
| November | 53°F | 38°F | 45.3°F | 7.64 | 18 | <1 | 8 | 9 h 40 min |
| December | 47°F | 34°F | 40.4°F | 8.40 | 20 | <1 | 12 | 8 h 50 min |
| Year (annual) | 63°F | 42°F | 52.4°F | 54.45 | 159 | 17 | 55 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 9°C | 1°C | 4.9°C | 182 mm |
| February | 11°C | 1°C | 6.0°C | 141 mm |
| March | 13°C | 3°C | 7.9°C | 159 mm |
| April | 16°C | 4°C | 9.9°C | 136 mm |
| May | 19°C | 7°C | 13.1°C | 97 mm |
| June | 23°C | 9°C | 15.8°C | 62 mm |
| July | 28°C | 11°C | 19.1°C | 14 mm |
| August | 28°C | 10°C | 19.1°C | 16 mm |
| September | 25°C | 8°C | 16.4°C | 51 mm |
| October | 18°C | 5°C | 11.7°C | 118 mm |
| November | 12°C | 3°C | 7.4°C | 194 mm |
| December | 8°C | 1°C | 4.7°C | 213 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353047; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
Which months are mildest at Foster Dam?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (3).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353047.
When is the last frost at Foster Dam?
In Foster Dam, the last spring frost (32°F) comes after April 12 in half of years and after May 5 in one year in ten; the first autumn frost comes before October 28 in half of years and before October 5 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 121 year in 10 after May 5; 9 in 10 after March 16
- First autumn frost, half of years before
- October 281 year in 10 before October 5; 9 in 10 before November 21
NOAA puts the median frost-free season at 197 days, and the season without a hard freeze (28°F) at 252 days.
A hard freeze (28°F) comes after March 9 in half of springs and before November 18 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Foster Dam in zone 8b in ZIP code 97386, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 8b: the coldest night of a typical year reaches 19°F (26 complete years).
Frost dates for every NOAA station in Oregon · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00353047; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Foster Dam?
In a normal year in Foster Dam, 17 days a year reach 90°F (1 of them 100°F or more), 55 nights fall to 32°F or colder and 159 days bring measurable precipitation.
- Days at 90°F or more
- 17a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 55a normal year
- Days that stay below freezing
- 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 159a normal year
The highest temperature in this station's record (since 1969) is 112°F, on June 29, 2021; the lowest is 0°F, on January 1, 1979.
The wettest calendar year on that record is 1996, with 86.33 in; the snowiest season is 1970–71, with 15.3 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00353047; records: ACIS (NOAA Regional Climate Centers), station USC00353047. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Foster Dam?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds at Foster Dam, 3.9 kWh per square metre a day. July is the sunniest month (89%) and December the cloudiest (53%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.3 |
| February | 61% | 2.2 |
| March | 59% | 3.1 |
| April | 64% | 4.5 |
| May | 70% | 5.7 |
| June | 74% | 6.4 |
| July | 89% | 7.4 |
| August | 88% | 6.3 |
| September | 81% | 4.6 |
| October | 70% | 2.8 |
| November | 58% | 1.5 |
| December | 53% | 1.1 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How many heating and cooling degree days does Foster Dam record?
A normal year at Foster Dam brings 4,811 heating degree days, 10% fewer than the median U.S. place (5,373), and 233 cooling degree days, 74% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,111 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 747 | 0 |
| February | 620 | 0 |
| March | 583 | 0 |
| April | 452 | 1 |
| May | 302 | 6 |
| June | 160 | 22 |
| July | 44 | 86 |
| August | 43 | 88 |
| September | 132 | 30 |
| October | 373 | 1 |
| November | 593 | 0 |
| December | 763 | 0 |
| Year (annual) | 4,811 | 233 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00353047. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Have recent years at Foster Dam been warmer than normal?
2024 averaged 53.1°F, 0.7°F above the 1991-2020 normal of 52.4°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 53.8°F | +1.4°F | 47.28 |
| 2022 | 52.4°F | at normal | 49.62 |
| 2023 | 52.8°F | +0.4°F | 41.20 |
| 2024 | 53.1°F | +0.7°F | 55.55 |
Over 48 complete years from 1970 to 2024, the station's annual mean temperature rose at a fitted 2.4°F per century (+0.14°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00353047; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Foster Dam's climate compare?
Foster Dam is warmer than 58 of the 105 places with their own NOAA record in Oregon, and wetter than 71. Across the 7,247 U.S. stations with normals, its annual mean of 52.4°F is warmer than 51%.
In the Köppen classification computed from these normals, Foster Dam is Csb: temperate, dry-summer, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Foster Dam share this climate record?
3 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Sweet Home, OR10,265 people · 2 mi SW
- Crawfordsville, OR528 people · 10 mi SW
- Holley, OR259 people · 7 mi SW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Foster Dam's climate
What is the coldest month at Foster Dam?
December, with a normal high of 47°F and a normal low of 34°F. The warmest is July (82°F by day, 51°F at night).
Does it snow at Foster Dam?
Rarely: NOAA's normal is 0.1 inch a year.
What is the rainiest month at Foster Dam?
December, with 8.40 in of precipitation in a normal year; the driest is July with 0.54 in.
What plant hardiness zone is Foster Dam in?
The USDA's 2023 map puts Foster Dam in zone 8b in ZIP code 97386, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 19°F (26 years, 1991-2020): zone 8b.
How late can frost come at Foster Dam?
In half of years the last 32°F night comes after April 12; in one year in ten it comes after May 5. Waiting until May 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- Cascadia, OR9 miles from this station, 50.1°F a year
- Lebanon, OR14 miles from this station, 54.9°F a year
- Lacomb, OR15 miles from this station, 51.4°F a year
- Leaburg (1 mi SW), OR22 miles from this station, 53.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made