Seneca, Oregon climate: Normal weather by month, frost dates and records
Seneca's normal year runs from 11°F December nights to 82°F July afternoons, with 13.7 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 4.7°C, December lows of −12°C, July highs of 28°C, 347 mm of precipitation a year.
- NOAA stationSeneca
- Station IDUSC00357675
- Location44.14°N 118.97°W
- Elevation4,660 ft (1,420 m)
- From the centerunder 1 mile
- Population162
On October 22, the normal high in Seneca is 56°F and the normal low 21°F, and the chance of measurable rain or snow is 27%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Seneca.
- Jan 36° 11°
- Feb 40° 14°
- Mar 46° 20°
- Apr 53° 25°
- May 62° 32°
- Jun 70° 36°
- Jul 82° 39°
- Aug 82° 35°
- Sep 73° 27°
- Oct 60° 21°
- Nov 44° 17°
- Dec 36° 11°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Seneca each month?
July is the warmest month, with normal highs of 82°F; December the coldest, with normal lows of 11°F. The most precipitation falls in December (1.82 in), the least in August (0.38 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 36°F | 11°F | 23.5°F | 1.58 | 12 | <1 | 30 | 9 h 10 min |
| February | 40°F | 14°F | 26.8°F | 1.01 | 10 | <1 | 27 | 10 h 30 min |
| March | 46°F | 20°F | 33.1°F | 1.23 | 11 | <1 | 29 | 11 h 50 min |
| April | 53°F | 25°F | 38.8°F | 1.18 | 11 | <1 | 25 | 13 h 20 min |
| May | 62°F | 32°F | 46.8°F | 1.71 | 10 | <1 | 16 | 14 h 40 min |
| June | 70°F | 36°F | 53.1°F | 1.19 | 7 | 1 | 7 | 15 h 30 min |
| July | 82°F | 39°F | 60.3°F | 0.53 | 4 | 6 | 4 | 15 h 10 min |
| August | 82°F | 35°F | 58.4°F | 0.38 | 3 | 6 | 10 | 14 h |
| September | 73°F | 27°F | 50.3°F | 0.53 | 4 | 1 | 21 | 12 h 40 min |
| October | 60°F | 21°F | 40.5°F | 1.07 | 8 | <1 | 27 | 11 h 10 min |
| November | 44°F | 17°F | 30.8°F | 1.44 | 12 | <1 | 28 | 9 h 40 min |
| December | 36°F | 11°F | 23.4°F | 1.82 | 13 | <1 | 30 | 8 h 50 min |
| Year (annual) | 57°F | 24°F | 40.5°F | 13.67 | 103 | 13 | 252 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 2°C | −12°C | −4.7°C | 40 mm |
| February | 4°C | −10°C | −2.9°C | 26 mm |
| March | 8°C | −7°C | 0.6°C | 31 mm |
| April | 11°C | −4°C | 3.8°C | 30 mm |
| May | 17°C | 0°C | 8.2°C | 43 mm |
| June | 21°C | 2°C | 11.7°C | 30 mm |
| July | 28°C | 4°C | 15.7°C | 13 mm |
| August | 28°C | 2°C | 14.7°C | 10 mm |
| September | 23°C | −3°C | 10.2°C | 13 mm |
| October | 15°C | −6°C | 4.7°C | 27 mm |
| November | 7°C | −8°C | −0.7°C | 37 mm |
| December | 2°C | −12°C | −4.8°C | 46 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, John Day (20 miles away), gets 10 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00357675; 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.
When is the best weather to visit Seneca?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, August 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 USC00357675.
How hot and how cold does it get in Seneca?
In a normal year in Seneca, 13 days a year reach 90°F, 252 nights fall to 32°F or colder and 103 days bring measurable precipitation.
- Days at 90°F or more
- 13a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 252a normal year
- Days that stay below freezing
- 26high of 32°F or less
- Days with 0.01 inch of precipitation
- 103a normal year
The highest temperature in this station's record (since 1912) is 104°F, on July 24, 1933; the lowest is −43°F, on January 26, 1957.
The wettest calendar year on that record is 1998, with 19.32 in; the snowiest season is 1955–56, with 145.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00357675; records: ACIS (NOAA Regional Climate Centers), station USC00357675. Records use complete months only; a month missing more than three days is left out.
How sunny is Seneca?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Seneca, 4.3 kWh per square metre a day. July is the sunniest month (91%) and December the cloudiest (57%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.6 |
| February | 68% | 2.6 |
| March | 67% | 3.6 |
| April | 71% | 5.1 |
| May | 73% | 6.1 |
| June | 80% | 7.1 |
| July | 91% | 7.7 |
| August | 89% | 6.5 |
| September | 85% | 5.0 |
| October | 76% | 3.2 |
| November | 65% | 1.8 |
| December | 57% | 1.2 |
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 much heating and cooling does Seneca need?
A normal year in Seneca brings 8,956 heating degree days, 67% more than the median U.S. place (5,373), and 37 cooling degree days, 96% fewer than the median (908). Ten months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 899 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,286 | 0 |
| February | 1,070 | 0 |
| March | 989 | 0 |
| April | 784 | 0 |
| May | 566 | 0 |
| June | 360 | 3 |
| July | 169 | 23 |
| August | 215 | 11 |
| September | 440 | 1 |
| October | 760 | 0 |
| November | 1,028 | 0 |
| December | 1,289 | 0 |
| Year (annual) | 8,956 | 37 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00357675. 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.
How does Seneca's climate compare?
Seneca is warmer than 0 of the other 104 places with their own NOAA record in Oregon, and wetter than 21. Across the 7,247 U.S. stations with normals, its annual mean of 40.5°F is warmer than 6%.
In the Köppen classification computed from these normals, Seneca is Dsb: continental, 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.
Questions about Seneca's climate
What is the coldest month in Seneca?
December, with a normal high of 36°F and a normal low of 11°F. The warmest is July (82°F by day, 39°F at night).
Does it snow in Seneca?
Yes. NOAA publishes no 1991-2020 snowfall normal for Seneca's NOAA station; the nearest record that keeps one, John Day (20 miles away), records 10 inches of snow in a normal year.
What is the rainiest month in Seneca?
December, with 1.82 in of precipitation in a normal year; the driest is August with 0.38 in.
What plant hardiness zone is Seneca in?
The USDA's 2023 map puts Seneca in zone 5b in ZIP code 97873, the nearest ZIP area. By the same method at Seneca's NOAA station, the coldest night of a typical year reaches −20°F (22 years, 1991-2020): zone 4b.
Nearby and next
- Oregon climateThe statewide normals and every place in the state
- John Day, OR20 miles from this station, 46.8°F a year
- Drewsey, OR37 miles from this station, 45.9°F a year
- Burns, OR37 miles from this station, 46.0°F a year
- Austin (3 mi S), OR39 miles from this station, 42.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made