Startup, Washington climate: Normal weather by month, frost dates and records
Startup's normal year runs from 34°F December nights to 78°F August afternoons, with 68.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.9°C, December lows of 1°C, August highs of 26°C, 1,735 mm of precipitation a year.
- NOAA stationStartup (1 mi E)
- Station IDUSC00458034
- Location47.87°N 121.72°W
- Elevation170 ft (52 m)
- Population (census place)746
On October 23, the normal high in Startup is 59°F and the normal low 40°F, and the chance of measurable rain or snow is 59%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Startup.
- Jan 47° 34°
- Feb 51° 34°
- Mar 55° 36°
- Apr 60° 39°
- May 67° 44°
- Jun 71° 49°
- Jul 78° 52°
- Aug 78° 51°
- Sep 73° 47°
- Oct 62° 42°
- Nov 52° 37°
- 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 in Startup each month?
August is the warmest month, with normal highs of 78°F; December the coldest, with normal lows of 34°F. The most precipitation falls in November (9.82 in), the least in July (1.48 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 47°F | 34°F | 40.7°F | 8.94 | 20 | <1 | 12 | 8 h 50 min |
| February | 51°F | 34°F | 42.4°F | 5.92 | 17 | <1 | 11 | 10 h 10 min |
| March | 55°F | 36°F | 45.4°F | 6.77 | 20 | <1 | 7 | 11 h 50 min |
| April | 60°F | 39°F | 49.6°F | 5.87 | 18 | <1 | 2 | 13 h 40 min |
| May | 67°F | 44°F | 55.5°F | 4.95 | 15 | <1 | <1 | 15 h 10 min |
| June | 71°F | 49°F | 59.7°F | 3.84 | 14 | 1 | <1 | 16 h |
| July | 78°F | 52°F | 64.6°F | 1.48 | 7 | 2 | <1 | 15 h 40 min |
| August | 78°F | 51°F | 64.9°F | 1.70 | 7 | 2 | <1 | 14 h 20 min |
| September | 73°F | 47°F | 59.9°F | 3.49 | 11 | 1 | <1 | 12 h 40 min |
| October | 62°F | 42°F | 51.7°F | 7.13 | 17 | <1 | 2 | 11 h |
| November | 52°F | 37°F | 44.6°F | 9.82 | 20 | <1 | 7 | 9 h 20 min |
| December | 47°F | 34°F | 40.0°F | 8.41 | 20 | <1 | 11 | 8 h 30 min |
| Year (annual) | 62°F | 42°F | 51.6°F | 68.32 | 186 | 5 | 53 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 9°C | 1°C | 4.8°C | 227 mm |
| February | 10°C | 1°C | 5.8°C | 150 mm |
| March | 13°C | 2°C | 7.4°C | 172 mm |
| April | 16°C | 4°C | 9.8°C | 149 mm |
| May | 19°C | 7°C | 13.1°C | 126 mm |
| June | 22°C | 9°C | 15.4°C | 98 mm |
| July | 25°C | 11°C | 18.1°C | 38 mm |
| August | 26°C | 11°C | 18.3°C | 43 mm |
| September | 23°C | 8°C | 15.5°C | 89 mm |
| October | 17°C | 5°C | 10.9°C | 181 mm |
| November | 11°C | 3°C | 7.0°C | 249 mm |
| December | 8°C | 1°C | 4.4°C | 214 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Tolt S Fork Reservoir (12 miles away), gets 55 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00458034; 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 Startup?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (7).
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 USC00458034.
When is the last frost in Startup?
In Startup, the last spring frost (32°F) comes after April 15 in half of years and after May 7 in one year in ten; the first autumn frost comes before October 25 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 151 year in 10 after May 7; 9 in 10 after March 25
- First autumn frost, half of years before
- October 251 year in 10 before October 5; 9 in 10 before November 15
NOAA puts the median frost-free season at 192 days, and the season without a hard freeze (28°F) at 240 days.
A hard freeze (28°F) comes after March 18 in half of springs and before November 12 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Startup in zone 8b in ZIP code 98294, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Startup's NOAA station is in zone 8b: the coldest night of a typical year reaches 18°F (23 complete years).
Frost dates for every NOAA station in Washington · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00458034; 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 in Startup?
In a normal year in Startup, 5 days a year reach 90°F, 53 nights fall to 32°F or colder and 186 days bring measurable precipitation.
- Days at 90°F or more
- 5a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 53a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 186a normal year
The highest temperature in this station's record (since 1924) is 106°F, on June 25, 1925; the lowest is −8°F, on January 25, 1950.
The wettest calendar year on that record is 1959, with 85.34 in; the snowiest season is 1964–65, with 60.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00458034; records: ACIS (NOAA Regional Climate Centers), station USC00458034. Records use complete months only; a month missing more than three days is left out.
How sunny is Startup?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Startup, 3.8 kWh per square metre a day. July is the sunniest month (86%) and December the cloudiest (54%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 56% | 1.2 |
| February | 64% | 2.1 |
| March | 63% | 3.1 |
| April | 67% | 4.6 |
| May | 70% | 5.7 |
| June | 74% | 6.3 |
| July | 86% | 7.0 |
| August | 85% | 5.9 |
| September | 79% | 4.3 |
| October | 69% | 2.5 |
| November | 58% | 1.3 |
| December | 54% | 0.9 |
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 Startup need?
A normal year in Startup brings 5,024 heating degree days, 6% fewer than the median U.S. place (5,373), and 147 cooling degree days, 84% 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 1,904 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 753 | 0 |
| February | 634 | 0 |
| March | 608 | 0 |
| April | 463 | 1 |
| May | 301 | 7 |
| June | 174 | 17 |
| July | 67 | 55 |
| August | 58 | 55 |
| September | 166 | 13 |
| October | 414 | 0 |
| November | 612 | 0 |
| December | 773 | 0 |
| Year (annual) | 5,024 | 147 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00458034. 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.
Has Startup been warmer than normal lately?
2025 averaged 52.8°F, 1.1°F above the 1991-2020 normal of 51.6°F. 2 of the 2 complete years since 2023 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2023 | 52.3°F | +0.7°F | 58.61 |
| 2025 | 52.8°F | +1.1°F | 59.90 |
Over 63 complete years from 1925 to 2025, the station's annual mean temperature rose at a fitted 2.3°F per century (+0.13°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00458034; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Startup's climate compare?
Startup is warmer than 74 of the other 95 places with their own NOAA record in Washington, and wetter than 76. Across the 7,247 U.S. stations with normals, its annual mean of 51.6°F is warmer than 48%.
In the Köppen classification computed from these normals, Startup 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 Startup share this climate record?
4 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.
- Sultan, WA7,002 people · 4 mi W
- Gold Bar, WA2,478 people · 1 mi SE
- May Creek, WA801 people · 2 mi E
- North Sultan, WA295 people · 5 mi W
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 Startup's climate
What is the coldest month in Startup?
December, with a normal high of 47°F and a normal low of 34°F. The warmest is August (78°F by day, 51°F at night).
Does it snow in Startup?
Yes. NOAA publishes no 1991-2020 snowfall normal for Startup's NOAA station; the nearest record that keeps one, Tolt S Fork Reservoir (12 miles away), records 55 inches of snow in a normal year.
What is the rainiest month in Startup?
November, with 9.82 in of precipitation in a normal year; the driest is July with 1.48 in.
What plant hardiness zone is Startup in?
The USDA's 2023 map puts Startup in zone 8b in ZIP code 98294, the nearest ZIP area. By the same method at Startup's NOAA station, the coldest night of a typical year reaches 18°F (23 years, 1991-2020): zone 8b.
How late can frost come in Startup?
In half of years the last 32°F night comes after April 15; in one year in ten it comes after May 7. Waiting until May 7 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Washington climateThe statewide normals and every place in the state
- Tolt S Fork Reservoir, WA12 miles from this station, 48.1°F a year
- Baring, WA12 miles from this station, 49.7°F a year
- Monroe, WA13 miles from this station, 49.5°F a year
- Snoqualmie, WA23 miles from this station, 51.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made