Duncan climate — normals and trends
Duncan (United States) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 16.8 °C and it receives 804 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (28.7 °C on average) and the coldest is January (4.0 °C). Rainfall peaks in May.
Duncan averages 50 frost days, 105 hot days (≥ 30 °C) and 83 rainy days per year.
Duncan has warmed by +1.7 °C between 1940 and 2025, or +0.20 °C per decade. This trend is statistically significant.
The number of frost days there went from about 54 to 46 per year over the period.
The hottest day of the period reached 44.2 °C (on 19 July 2022) and the coldest -26.3 °C (on 12 March 1948).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
DuncanOklahoma
- coords
- 34.50°, -97.96°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
16.8°C
Average daily high
22.6°C
Average daily low
11.6°C
Annual rainfall
804mm
Sunshine / day
9.8h
Mean relative humidity
62%
Average peak wind
19.7km/h
Seasonal range
24.7°C
Frost days (< 0 °C)
50 d/yr
Hot days (≥ 30 °C)
105 d/yr
Rainy days (≥ 1 mm)
83 d/yr
Annual snowfall
12.5 cm
Average feels-like high
21.7 °C
Average feels-like low
9.6 °C
Average peak gust
39.6 km/h
Tropical nights (≥ 20 °C)
97 d/yr
Solar radiation
17.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.34 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
44.2 °C
19 July 2022
Coldest day
-26.3 °C
12 March 1948
Wettest day
103 mm
22 October 2015
Windiest day
48.3 km/h
24 February 2007
Strongest gust
97.2 km/h
26 February 2023
Hottest feels-like
45.1 °C
9 August 2011
Coldest feels-like
-31.1 °C
12 March 1948
Snowiest day
18.6 cm
11 March 1968
Sunniest day
14.0 h
28 June 2023
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 9.1 °C | -0.8 °C | 16 mm | -22 mm |
| Feb | 12.6 °C | -0.1 °C | 13 mm | -33 mm |
| Mar | 23.1 °C | +5.5 °C | 61 mm | -17 mm |
| Apr | 23.6 °C | +1.0 °C | 331 mm | +230 mm |
| May | 26.5 °C | -0.2 °C | 173 mm | +48 mm |
| Jun | 31.7 °C | +0.2 °C | 70 mm | -9 mm |
| Jul | 34.0 °C | -0.2 °C | 45 mm | +1 mm |
| Aug | 33.2 °C | -1.0 °C | 41 mm | -2 mm |
| Sep | 31.5 °C | +1.8 °C | 16 mm | -56 mm |
| Oct | 27.4 °C | +3.6 °C | 22 mm | -61 mm |
| Nov | 21.7 °C | +5.0 °C | 35 mm | -17 mm |
| Dec | 16.0 °C | +4.5 °C | 5 mm | -38 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Duncan?
Duncan has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 16.8 °C and it receives 804 mm of precipitation per year.
What is the hottest day ever recorded in Duncan?
The hottest day measured in Duncan between 1940 and 2025 was 19 July 2022, reaching 44.2 °C.
What is the coldest day in Duncan?
The coldest day measured in Duncan between 1940 and 2025 was 12 March 1948, at -26.3 °C.
Does it snow in Duncan?
Yes. Duncan gets on average 12.5 cm of snow per year and has around 50 frost days.
Has the climate of Duncan warmed?
Yes: Duncan warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Duncan?
The wettest day measured in Duncan between 1940 and 2025 was 22 October 2015, with 103 mm of rain in 24 hours.
What was the windiest day in Duncan?
The windiest day measured in Duncan between 1940 and 2025 was 24 February 2007, with winds reaching 48.3 km/h.
What is the warmest month in Duncan?
The warmest month in Duncan is July (28.7 °C on average); the coldest is January (4.0 °C).
How much does it rain in Duncan?
Duncan receives on average 804 mm of precipitation per year, spread over about 83 rainy days.
Is it sunny in Duncan?
Duncan gets on average 9.8 hours of sunshine per day, roughly 3,577 hours per year over 1940-2025.
What is the biggest single-day snowfall in Duncan?
The heaviest 24-hour snowfall measured in Duncan between 1940 and 2025 was 11 March 1968, with 18.6 cm.
Are there tropical nights in Duncan?
Yes: Duncan has on average 97 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Duncan?
In Duncan, between 1940 and 2025, the highest apparent temperature reached 45.1 °C on 9 August 2011, and the lowest was -31.1 °C on 12 March 1948.
Compare Duncan with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Duncan