Stillwater, Oklahoma climate: Normal weather by month, frost dates and records
Stillwater's normal year runs from 27°F January nights to 95°F July afternoons, with 33.2 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 16.4°C, January lows of −3°C, July highs of 35°C, 843 mm of precipitation a year.
- NOAA stationStillwater Regional Airport
- Station IDUSW00003965
- Location36.16°N 97.09°W
- Elevation984 ft (300 m)
- From the center2 miles
- Population50,138
On October 23, the normal high in Stillwater is 73°F and the normal low 47°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Stillwater.
- Jan 51° 27°
- Feb 56° 31°
- Mar 65° 40°
- Apr 73° 49°
- May 81° 59°
- Jun 90° 68°
- Jul 95° 72°
- Aug 95° 71°
- Sep 87° 62°
- Oct 75° 49°
- Nov 63° 38°
- Dec 52° 30°
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 Stillwater each month?
July is the warmest month, with normal highs of 95°F; January the coldest, with normal lows of 27°F. The most precipitation falls in May (4.58 in), the least in January (0.92 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 51°F | 27°F | 38.7°F | 0.92 | 4 | <1 | 24 | 10 h |
| February | 56°F | 31°F | 43.1°F | 1.33 | 6 | <1 | 18 | 10 h 50 min |
| March | 65°F | 40°F | 52.1°F | 2.22 | 7 | <1 | 9 | 11 h 50 min |
| April | 73°F | 49°F | 60.9°F | 3.72 | 8 | 1 | 2 | 13 h |
| May | 81°F | 59°F | 69.7°F | 4.58 | 11 | 5 | <1 | 14 h |
| June | 90°F | 68°F | 78.6°F | 4.49 | 9 | 16 | <1 | 14 h 40 min |
| July | 95°F | 72°F | 83.7°F | 3.12 | 7 | 25 | <1 | 14 h 20 min |
| August | 95°F | 71°F | 82.7°F | 3.28 | 7 | 24 | <1 | 13 h 30 min |
| September | 87°F | 62°F | 74.3°F | 3.11 | 7 | 11 | <1 | 12 h 30 min |
| October | 75°F | 49°F | 62.3°F | 2.94 | 8 | 2 | 2 | 11 h 20 min |
| November | 63°F | 38°F | 50.3°F | 1.95 | 5 | <1 | 10 | 10 h 20 min |
| December | 52°F | 30°F | 40.9°F | 1.51 | 5 | <1 | 22 | 9 h 40 min |
| Year (annual) | 74°F | 49°F | 61.5°F | 33.17 | 82 | 83 | 87 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 10°C | −3°C | 3.7°C | 23 mm |
| February | 13°C | −1°C | 6.2°C | 34 mm |
| March | 18°C | 4°C | 11.2°C | 56 mm |
| April | 23°C | 9°C | 16.1°C | 94 mm |
| May | 27°C | 15°C | 20.9°C | 116 mm |
| June | 32°C | 20°C | 25.9°C | 114 mm |
| July | 35°C | 22°C | 28.7°C | 79 mm |
| August | 35°C | 21°C | 28.2°C | 83 mm |
| September | 30°C | 17°C | 23.5°C | 79 mm |
| October | 24°C | 10°C | 16.8°C | 75 mm |
| November | 17°C | 3°C | 10.2°C | 50 mm |
| December | 11°C | −1°C | 4.9°C | 38 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. Stillwater's own co-op station Stillwater (2 mi W) does: 8 inches of snow in a normal year (see the other stations below).
Source: NOAA NCEI 1991-2020 monthly normals, station USW00003965; 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 Stillwater?
Normal highs sit between 65°F and 85°F in April, May and October. Of those, April has the fewest days with rain (8).
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 USW00003965.
When is the last frost in Stillwater?
In Stillwater, the last spring frost (32°F) comes after April 3 in half of years and after April 21 in one year in ten; the first autumn frost comes before October 31 in half of years and before October 15 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 31 year in 10 after April 21; 9 in 10 after March 18
- First autumn frost, half of years before
- October 311 year in 10 before October 15; 9 in 10 before November 14
NOAA puts the median frost-free season at 209 days, and the season without a hard freeze (28°F) at 230 days.
A hard freeze (28°F) comes after March 23 in half of springs and before November 8 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Stillwater in zone 7a across its 3 ZIP code areas (7a in 74075, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Stillwater's NOAA station is in zone 7a: the coldest night of a typical year reaches 3°F (22 complete years).
Frost dates for every NOAA station in Oklahoma · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00003965; 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.
What hardiness zone is each Stillwater ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Stillwater's 3 ZIP code areas are all in zone 7a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Stillwater?
In a normal year in Stillwater, 83 days a year reach 90°F (17 of them 100°F or more), 87 nights fall to 32°F or colder and 82 days bring measurable precipitation.
- Days at 90°F or more
- 83a normal year
- Days at 100°F or more
- 17a normal year
- Nights at 32°F or colder
- 87a normal year
- Days that stay below freezing
- 8high of 32°F or less
- Days with 0.01 inch of precipitation
- 82a normal year
The highest temperature in Stillwater's official record (kept by the National Weather Service since 1893) is 115°F, on August 11, 1936; the lowest is −21°F, on February 10, 2011.
The wettest calendar year on that record is 1959, with 61.87 in; the snowiest season is 1987–88, with 30.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00003965; records: ACIS (NOAA Regional Climate Centers), NWS threaded record SWOthr. Records use complete months only; a month missing more than three days is left out.
How sunny is Stillwater?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Stillwater, 4.7 kWh per square metre a day. July is the sunniest month (87%) and February the cloudiest (74%). Among the 459 U.S. places of 50,000 or more, that ranks tied 125th (with 50 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 77% | 2.7 |
| February | 74% | 3.4 |
| March | 74% | 4.4 |
| April | 76% | 5.5 |
| May | 77% | 6.1 |
| June | 86% | 7.0 |
| July | 87% | 6.9 |
| August | 86% | 6.1 |
| September | 84% | 5.1 |
| October | 80% | 3.9 |
| November | 80% | 2.9 |
| December | 74% | 2.3 |
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 Stillwater need?
A normal year in Stillwater brings 3,449 heating degree days, 36% fewer than the median U.S. place (5,373), and 2,194 cooling degree days, 2.4 times the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 5,389 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 815 | 0 |
| February | 615 | 2 |
| March | 416 | 18 |
| April | 185 | 63 |
| May | 41 | 186 |
| June | 1 | 409 |
| July | 0 | 581 |
| August | 0 | 550 |
| September | 16 | 295 |
| October | 163 | 81 |
| November | 449 | 8 |
| December | 748 | 1 |
| Year (annual) | 3,449 | 2,194 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00003965. 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 Stillwater been warmer than normal lately?
2025 averaged 61.3°F, 0.2°F below the 1991-2020 normal of 61.5°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 62.0°F | +0.5°F | 25.17 |
| 2022 | 62.1°F | +0.6°F | 27.32 |
| 2023 | 62.8°F | +1.3°F | 31.99 |
| 2024 | 64.4°F | +2.9°F | 26.28 |
| 2025 | 61.3°F | −0.2°F | – |
Source: observed years: ACIS, station USW00003965. A year counts only with all twelve months complete.
How does Stillwater's climate compare?
Stillwater is warmer than 101 of the other 133 places with their own NOAA record in Oklahoma, and wetter than 36. Across the 7,247 U.S. stations with normals, its annual mean of 61.5°F is warmer than 78%.
In the Köppen classification computed from these normals, Stillwater is Cfa: temperate, no dry season, hot 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 Stillwater share this climate record?
2 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.
- Glencoe, OK516 people · 10 mi NE
- Lone Chimney, OK78 people · 17 mi E
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Stillwater's other NOAA stations record?
4 more NOAA stations keep 1991-2020 normals in or near Stillwater. This page uses Stillwater Regional Airport; the others differ by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Stillwater (2 mi W) USW00053926 | 1 mi SW | 890 ft | 60.2°F | 26°F | 94°F | 36.0 | – | April 5 |
| Stillwater (2 mi W) USC00348501 | 1 mi SW | 895 ft | 59.6°F | 23°F | 93°F | 36.7 | 8 | April 8 |
| Stillwater (5 mi WNW) USW00053927 | 2 mi W | 888 ft | 59.1°F | 24°F | 93°F | 36.2 | – | April 12 |
| Stillwater Mesonet USC00348499 | 1 mi SW | 892 ft | 60.1°F | 26°F | 93°F | – | – | April 6 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Stillwater's climate
What is the coldest month in Stillwater?
January, with a normal high of 51°F and a normal low of 27°F. The warmest is July (95°F by day, 72°F at night).
Does it snow in Stillwater?
Yes. NOAA publishes no 1991-2020 snowfall normal for Stillwater's NOAA station; Stillwater's own co-op station Stillwater (2 mi W) records 8 inches of snow in a normal year.
What is the rainiest month in Stillwater?
May, with 4.58 in of precipitation in a normal year; the driest is January with 0.92 in.
What plant hardiness zone is Stillwater in?
The USDA's 2023 map puts Stillwater in zone 7a across its 3 ZIP code areas (7a in 74075, the largest). By the same method at Stillwater's NOAA station, the coldest night of a typical year reaches 3°F (22 years, 1991-2020): zone 7a.
How late can frost come in Stillwater?
In half of years the last 32°F night comes after April 3; in one year in ten it comes after April 21. Waiting until April 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Oklahoma climateThe statewide normals and every place in the state
- Coyle, OK10 miles from this station, 60.0°F a year
- Orlando, OK11 miles from this station, 59.2°F a year
- Perkins, OK12 miles from this station, 60.4°F a year
- Red Rock, OK14 miles from this station, 59.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made