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Duncan, Oklahoma climate
Cfa Humid subtropical
Duncan has a seasonal mild-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 96°F, while the coldest is January averaging around 30°F at night. Precipitation totals about 32 inches a year and is strongly seasonal — May alone averages 4.9 inches while January barely receives 1.09 inches.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Duncan climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 54 | 59 | 68 | 75 | 82 | 91 | 96 | 95 | 87 | 77 | 64 | 54 |
| Avg temp (°F) | 42 | 47 | 56 | 63 | 71 | 80 | 85 | 84 | 76 | 64 | 53 | 44 |
| Avg low (°F) | 30 | 35 | 43 | 51 | 61 | 69 | 73 | 72 | 64 | 52 | 41 | 33 |
| Precipitation (in) | 1.1 | 1.4 | 2.3 | 3.6 | 4.9 | 4.2 | 2.6 | 2.8 | 3.3 | 2.6 | 1.8 | 1.9 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 54 | 59 | 68 | 75 | 82 | 91 |
| Avg temp (°F) | 42 | 47 | 56 | 63 | 71 | 80 |
| Avg low (°F) | 30 | 35 | 43 | 51 | 61 | 69 |
| Precipitation (in) | 1.1 | 1.4 | 2.3 | 3.6 | 4.9 | 4.2 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 96 | 95 | 87 | 77 | 64 | 54 |
| Avg temp (°F) | 85 | 84 | 76 | 64 | 53 | 44 |
| Avg low (°F) | 73 | 72 | 64 | 52 | 41 | 33 |
| Precipitation (in) | 2.6 | 2.8 | 3.3 | 2.6 | 1.8 | 1.9 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 52 | 55 | 57 | 53 | 55 | 47 | 40 | 43 | 42 | 42 | 46 | 52 |
| Relative humidity (%) | 70 | 69 | 67 | 64 | 68 | 66 | 57 | 56 | 61 | 63 | 68 | 72 |
| Wind speed (mph) | 7.0 | 7.4 | 8.0 | 8.3 | 7.5 | 7.0 | 6.4 | 6.0 | 6.3 | 7.1 | 7.1 | 6.7 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 52 | 55 | 57 | 53 | 55 | 47 |
| Relative humidity (%) | 70 | 69 | 67 | 64 | 68 | 66 |
| Wind speed (mph) | 7.0 | 7.4 | 8.0 | 8.3 | 7.5 | 7.0 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 40 | 43 | 42 | 42 | 46 | 52 |
| Relative humidity (%) | 57 | 56 | 61 | 63 | 68 | 72 |
| Wind speed (mph) | 6.4 | 6.0 | 6.3 | 7.1 | 7.1 | 6.7 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 25 years of daily observations at Henry Post Aaf Airport, a weather station, about 44 km from the city centre. The underlying daily records come from NOAA's global station network.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.