Average Statewide Temperature for Western U.S. States

Each month, averages of temperature are calculated for U.S. Climate Divisions by simply averaging the data from all stations within the division that record both temperature. A division represents a region within a state that is climatically quasi-homogeneous or, in some cases, a semi-homogeneous drainage basin.

The average monthly temperature for a state is derived from the divisional values by weighting each division by its percentage of the total state area.

Source: National Climatic Data Center, Historical Climatography Series 4-1.

            NORMALS    JAN   FEB   MAR   APR   MAY   JUN   JUL   AUG   SEP   OCT   NOV   DEC   YEAR
 
 Alaska     1931-60    0.2   3.9   9.6  24.3  38.6  49.7  53.5  50.9  42.5  28.7  12.6   2.2   26.4
            1941-70    0.6   3.9   9.7  23.3  38.6  49.5  53.5  50.9  42.6  27.5  12.3   1.5   26.2
            1951-80   -0.2   2.2   8.8  22.9  38.5  49.2  53.6  51.3  42.5  26.7  12.3   0.9   25.7
            1961-90    1.4   2.6  10.4  22.8  38.8  49.6  54.2  51.4  42.7  26.4  11.1   3.4   26.2
            1971-00    1.1   3.1  10.7  23.9  39.5  50.3  54.9  51.8  42.6  26.2  11.2   3.9   26.6
 
 Arizona    1931-60   40.6  44.3  49.8  57.6  65.4  74.3  80.0  77.8  72.7  61.8  49.1  42.7   59.7
            1941-70   40.9  44.7  49.1  57.0  65.4  74.0  80.0  77.8  72.4  61.8  49.6  42.2   59.6
            1951-80   41.0  44.8  49.2  56.4  64.9  74.6  80.1  77.7  72.1  61.6  49.3  41.9   59.5
            1961-90   41.2  45.4  49.8  57.0  65.4  74.9  80.1  77.9  71.8  61.3  49.7  41.9   59.7
            1971-00   42.3  46.2  51.0  57.6  66.0  75.5  80.2  78.5  72.6  61.7  49.6  42.5   60.3
 
 California 1931-60   43.3  46.4  50.6  56.3  62.3  68.8  75.2  73.8  69.7  60.9  51.1  45.3   58.6
            1941-70   43.6  47.1  50.0  55.6  62.0  68.6  75.0  73.7  69.6  61.0  51.2  44.8   58.5
            1951-80   43.9  47.6  50.2  55.1  61.9  69.3  75.1  73.9  69.6  61.2  51.1  44.8   58.6
            1961-90   44.4  48.1  50.9  55.7  62.5  69.9  75.2  74.3  69.3  61.3  51.1  44.5   58.9
            1971-00   45.1  48.5  51.8  56.5  63.1  70.2  75.3  74.6  69.9  61.6  51.1  45.0   59.4
 
 Colorado   1931-60   23.8  27.3  33.6  43.5  52.9  62.3  68.2  66.6  58.8  48.1  34.1  26.8   45.5
            1941-70   23.7  27.4  32.6  43.2  52.9  61.6  67.8  65.9  58.0  47.7  34.3  26.2   45.1
            1951-80   23.1  27.4  33.1  42.6  52.6  62.1  67.9  65.6  57.7  47.4  33.7  25.7   44.9
            1961-90   22.9  27.4  34.0  43.0  52.4  61.8  67.8  65.5  57.3  46.8  34.2  24.8   44.8
            1971-00   23.7  28.3  35.6  43.1  52.5  62.2  67.6  65.7  57.7  46.6  33.5  25.2   45.1
 
 Hawaii     1931-60 -999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9 -999.9
            1941-70 -999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9 -999.9
            1951-80 -999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9-999.9 -999.9
            1961-90   67.0  66.9  67.5  68.4  69.8  71.3  72.1  72.7  72.7  72.0  70.2  68.1   69.9
            1971-00   67.0  67.0  67.7  68.5  69.7  71.4  72.3  73.0  72.9  72.2  70.4  68.2   70.0
 
 Idaho      1931-60   21.5  26.1  33.0  43.0  51.7  58.3  66.9  64.5  56.3  46.4  32.7  25.8   43.9
            1941-70   21.8  27.3  32.4  42.1  51.1  57.8  66.4  64.4  55.9  45.7  33.2  25.2   43.6
            1951-80   22.5  27.8  32.7  41.8  51.0  58.7  66.5  64.4  55.9  45.5  32.9  25.2   43.7
            1961-90   22.7  27.9  34.4  42.6  51.1  59.4  66.4  65.0  55.6  45.4  33.3  24.0   44.0
            1971-00   23.6  28.4  35.9  43.5  51.6  59.3  66.2  65.4  56.1  45.5  32.9  24.3   44.4
 
 Montana    1931-60   16.7  20.7  28.8  41.7  52.2  59.3  67.6  65.3  55.4  45.1  30.3  22.6   42.1
            1941-70   16.1  22.3  28.3  41.3  51.4  58.8  66.8  65.2  54.6  44.9  30.4  21.5   41.8
            1951-80   15.3  22.9  29.2  40.8  51.5  59.7  66.7  65.0  54.8  44.7  30.0  21.5   41.9
            1961-90   17.4  23.7  31.4  41.9  51.8  60.6  66.9  65.4  54.5  44.6  30.2  19.9   42.4
            1971-00   18.4  24.4  32.9  42.5  52.2  60.6  66.4  65.6  55.1  44.3  29.7  20.8   42.7
 
 Nevada     1931-60   29.2  33.4  39.8  48.0  56.0  64.2  72.6  70.4  62.4  51.3  38.8  32.1   49.8
            1941-70   29.5  34.3  38.7  46.7  55.4  63.2  71.9  69.6  61.7  51.0  38.9  31.3   49.4
            1951-80   29.9  34.9  39.0  46.0  55.1  64.1  72.0  69.6  61.5  50.9  38.7  31.1   49.4
            1961-90   29.7  34.9  39.8  46.4  55.3  64.5  71.9  69.8  61.0  50.6  38.7  30.5   49.4
            1971-00   30.4  35.5  41.2  47.3  55.7  64.8  71.9  70.2  61.6  50.6  38.4  30.9   49.9
 
 New Mexico 1931-60   33.8  37.8  43.5  52.1  60.6  70.0  73.4  71.9  65.5  55.1  42.1  35.5   53.4
            1941-70   33.8  37.8  42.8  52.0  60.8  69.5  73.6  71.8  65.2  54.9  42.6  35.2   53.3
            1951-80   33.9  37.7  43.3  51.5  60.3  69.7  73.6  71.3  64.8  54.6  42.2  35.0   53.2
            1961-90   33.5  37.9  43.9  51.8  60.4  69.3  73.3  71.0  64.4  54.3  42.8  34.8   53.1
            1971-00   34.4  38.9  44.9  51.8  60.7  69.7  73.2  71.3  64.8  54.3  42.4  34.9   53.4
 
 Oregon     1931-60   30.8  34.9  40.1  46.7  53.2  58.9  66.0  64.4  58.4  49.6  39.0  34.0   48.0
            1941-70   31.0  36.2  39.7  45.7  52.7  58.8  65.8  64.3  58.4  49.2  39.5  33.8   47.9
            1951-80   31.7  36.7  39.7  45.2  52.5  59.3  66.0  64.5  58.4  49.2  39.2  33.7   48.0
            1961-90   32.0  36.7  40.7  45.6  52.5  59.9  65.8  65.2  58.0  49.1  39.2  32.6   48.1
            1971-00   32.6  36.7  41.5  46.4  52.9  59.6  66.0  65.5  58.6  49.2  39.0  32.8   48.4
 
 Utah       1931-60   24.2  29.3  37.2  46.9  55.8  64.3  72.2  70.1  61.8  50.1  35.8  28.0   48.0
            1941-70   24.7  30.2  36.6  46.1  55.7  63.7  72.1  69.9  61.3  50.0  36.5  27.7   47.9
            1951-80   25.1  30.7  37.1  45.7  55.5  64.7  72.5  69.9  61.2  49.9  36.4  27.2   48.0
            1961-90   24.7  30.8  38.1  46.2  55.6  65.2  72.6  70.2  60.9  49.6  36.9  26.7   48.1
            1971-00   25.9  31.5  39.7  46.9  55.9  65.6  72.5  70.6  61.5  49.5  36.3  27.3   48.6
 
 Washington 1931-60   29.3  33.6  39.8  47.3  54.4  59.6  65.7  64.4  58.6  49.1  38.0  33.0   47.7
            1941-70   29.3  35.1  39.5  46.4  53.8  59.6  65.6  64.4  58.5  48.6  38.3  32.5   47.6
            1951-80   29.8  35.5  39.5  46.1  53.5  59.8  65.5  64.6  58.4  48.5  38.1  32.7   47.7
            1961-90   30.8  35.8  40.9  46.6  53.5  60.3  65.5  65.4  58.3  48.4  38.4  31.6   48.0
            1971-00   31.5  35.8  41.5  47.4  54.1  60.1  65.7  65.8  58.7  48.5  38.3  31.7   48.3
 
 Wyoming    1931-60   18.6  22.1  28.9  40.1  50.1  58.8  66.8  64.8  55.3  44.7  30.0  22.9   41.9
            1941-70   18.7  23.1  28.3  39.9  50.0  58.2  66.4  64.7  54.8  44.4  30.4  22.2   41.8
            1951-80   18.3  23.5  29.0  39.5  50.1  59.2  66.7  64.4  54.7  44.2  29.7  21.9   41.8
            1961-90   18.6  23.3  30.5  40.1  49.9  59.5  66.7  64.4  54.3  43.7  30.0  20.3   41.8
            1971-00   19.2  23.7  32.1  40.4  50.0  59.6  66.3  64.7  54.7  43.4  29.2  20.7   42.0