Industrial Production and Capacity Utilization - G.17

Federal Reserve Seasonal Factors for Domestic Auto and Truck Production

Release Date: March 15, 2024

Seasonal factors for auto and truck production were revised from January 2019 through June 2025 on March 15, 2024. The revised factors for September 2023 through February 2024 were used in the G.17 release issued on March 15, 2024, and the revised factors for earlier months will be incorporated into the production estimates at the time of the annual revision. The revised seasonal factors are based on production data through January 2024; in the estimation, production data for September through December 2023 are identified as outliers because of the United Auto Workers strike and subsequent rebound. The seasonal factors are scheduled to be revised again in March 2025.

Monthly figures for motor vehicle assemblies in millions of units at an annual rate are published in Table 3 of the G.17 release. The formula for seasonally adjusted annual rates (SAAR) of auto and truck production (in millions of units) for each month is 

       SAAR = ((NSA data in units/1,000,000) * 12)/(SF * .01).

The not seasonally adjusted (NSA) data are obtained from Ward's Communications, and the seasonal factors (SF), which contain adjustments for holiday and length-of-month effects as well as normal seasonal variation, are shown in the table below under "Regular Seasonal Factors."

The table below also shows a set of seasonal factors on a weekday average basis (SFW) in the columns under "Weekday-basis Seasonal Factors"; the number of production days in a month, or weekdays, is shown separately. Using this information, the formula for seasonally adjusted annual rates of auto and truck production (in millions of units) for each month is 

       SAAR = ((NSA data in units/1,000,000) * 260)/(weekdays * SFW * .01).

Multiplying by 260, the average number of weekdays in a year, converts the weekday average production to an annual production rate. This formula reduces to 

       SAAR = (NSA data in units * .026) / (weekdays * SFW).

A comma-delimited text file containing these seasonal factors (1996-2025) is available for download here.

    

Monthly Seasonal Factors for Domestic Auto and Truck Production
 
 
  		Regular Seasonal Factors Weekday-basis Seasonal Factors
 
Autos 		Total
Trucks 		Light
Trucks 		 
Autos 		Total
Trucks 		Light
Trucks 		 
Weekdays
Jan-2018 101.20  99.44  99.48  95.34  93.68  93.72 23
Feb-2018  99.76 100.89 101.24 108.08 109.29 109.67 20
Mar-2018 102.90 109.56 109.76 101.35 107.90 108.09 22
Apr-2018 102.83 101.08 100.77 106.10 104.29 103.97 21
May-2018 107.38 105.46 105.27 101.15  99.35  99.17 23
Jun-2018 101.84 101.51 101.40 105.08 104.74 104.62 21
Jul-2018  80.23  82.76  82.35  79.02  81.50  81.10 22
Aug-2018 111.54 112.70 113.29 105.08 106.17 106.72 23
Sep-2018  95.14  94.93  94.83 103.06 102.84 102.73 20
Oct-2018 117.37 115.69 115.71 110.56 108.99 109.00 23
Nov-2018 102.58  98.72  98.88 101.03  97.23  97.38 22
Dec-2018  78.72  78.52  78.36  81.22  81.01  80.85 21
Jan-2019 101.31  99.46  99.47  95.43  93.69  93.71 23
Feb-2019 100.06 100.26 100.63 108.39 108.62 109.01 20
Mar-2019 102.69 108.73 108.92 105.95 112.18 112.38 21
Apr-2019 103.86 101.80 101.56 102.29 100.26 100.03 22
May-2019 107.01 105.76 105.63 100.81  99.63  99.50 23
Jun-2019  96.50  96.45  96.35 104.54 104.49 104.38 20
Jul-2019  83.58  88.17  87.79  78.73  83.05  82.70 23
Aug-2019 107.47 107.95 108.48 105.84 106.31 106.83 22
Sep-2019 100.56  99.75  99.60 103.75 102.91 102.76 21
Oct-2019 117.69 115.88 115.91 110.87 109.17 109.19 23
Nov-2019 100.57  96.89  97.00 103.76  99.97 100.08 21
Dec-2019  83.41  83.88  83.65  82.15  82.61  82.38 22
Jan-2020 100.68  99.29  99.29  94.84  93.53  93.53 23
Feb-2020  99.98  99.99 100.37 108.32 108.33 108.73 20
Mar-2020 106.92 113.38 113.58 105.30 111.66 111.86 22
Apr-2020 104.35 101.66 101.46 102.77 100.12  99.92 22
May-2020  97.13  96.08  95.99 100.21  99.13  99.04 21
Jun-2020 105.40 105.76 105.66 103.81 104.16 104.06 22
Jul-2020  83.85  88.99  88.65  78.99  83.83  83.51 23
Aug-2020 102.82 103.14 103.63 106.09 106.41 106.92 21
Sep-2020 105.95 104.68 104.51 104.34 103.09 102.92 22
Oct-2020 113.05 110.99 111.01 111.34 109.30 109.33 22
Nov-2020  95.92  92.44  92.52  98.97  95.37  95.46 21
Dec-2020  88.67  89.25  88.99  83.53  84.08  83.83 23
Jan-2021  90.80  89.86  89.84  93.69  92.71  92.69 21
Feb-2021  99.89  99.69 100.06 108.22 108.00 108.40 20
Mar-2021 111.34 118.23 118.44 104.88 111.38 111.58 23
Apr-2021 104.46 101.35 101.17 102.87  99.82  99.63 22
May-2021  96.72  96.05  95.99  99.79  99.10  99.04 21
Jun-2021 105.01 105.34 105.24 103.42 103.75 103.64 22
Jul-2021  80.47  85.76  85.48  79.25  84.46  84.19 22
Aug-2021 107.79 108.31 108.84 106.16 106.67 107.19 22
Sep-2021 106.36 104.55 104.35 104.75 102.96 102.77 22
Oct-2021 108.19 105.86 105.86 111.63 109.22 109.22 21
Nov-2021 101.15  97.66  97.73  99.62  96.18  96.25 22
Dec-2021  88.81  89.36  89.08  83.66  84.18  83.91 23
Jan-2022  95.25  94.40  94.39  98.28  97.40  97.38 21
Feb-2022  99.53  99.24  99.62 107.82 107.51 107.92 20
Mar-2022 110.88 117.85 118.05 104.45 111.01 111.21 23
Apr-2022  99.29  96.09  95.92 102.45  99.14  98.97 21
May-2022 101.32 101.15 101.11  99.79  99.61  99.58 22
Jun-2022 104.54 104.82 104.70 102.95 103.23 103.12 22
Jul-2022  77.25  82.56  82.35  79.70  85.18  84.96 21
Aug-2022 112.91 113.43 113.97 106.37 106.85 107.36 23
Sep-2022 106.70 104.25 104.04 105.08 102.67 102.47 22
Oct-2022 108.43 105.81 105.79 111.87 109.17 109.15 21
Nov-2022 101.79  98.64  98.69 100.25  97.15  97.20 22
Dec-2022  88.69  89.27  88.96  87.35  87.92  87.61 22
Jan-2023  95.16  94.52  94.51  93.72  93.09  93.08 22
Feb-2023  99.31  98.87  99.24 107.58 107.11 107.51 20
Mar-2023 110.67 117.43 117.62 104.25 110.62 110.80 23
Apr-2023  94.18  91.00  90.87 102.02  98.58  98.44 20
May-2023 105.68 106.30 106.29  99.56 100.14 100.13 23
Jun-2023 104.21 104.18 104.06 102.63 102.60 102.48 22
Jul-2023  73.91  79.22  79.07  76.26  81.74  81.58 21
Aug-2023 113.19 113.59 114.15 106.62 107.00 107.53 23
Sep-2023 101.94  98.99  98.77 105.17 102.14 101.91 21
Oct-2023 113.77 110.96 110.91 112.05 109.28 109.23 22
Nov-2023 101.39  98.38  98.40  99.85  96.89  96.91 22
Dec-2023  83.33  83.96  83.64  85.97  86.63  86.30 21
Jan-2024  99.57  99.40  99.43  93.79  93.64  93.67 23
Feb-2024 103.83 103.22 103.59 107.13 106.49 106.87 21
Mar-2024  96.09 101.64 101.80  99.14 104.86 105.03 21
Apr-2024 109.32 105.46 105.34 107.67 103.86 103.74 22
May-2024 105.49 106.86 106.87  99.37 100.66 100.68 23
Jun-2024  94.38  94.11  93.97 102.24 101.95 101.80 20
Jul-2024  85.88  92.34  92.20  80.90  86.98  86.86 23
Aug-2024 108.65 108.60 109.15 107.01 106.95 107.49 22
Sep-2024 102.15  98.87  98.62 105.40 102.01 101.76 21
Oct-2024 119.19 116.36 116.30 112.28 109.61 109.56 23
Nov-2024  99.41  96.55  96.56 102.56  99.61  99.62 21
Dec-2024  77.99  78.62  78.30  76.80  77.43  77.12 22
Jan-2025  98.63  99.10  99.16  92.91  93.35  93.41 23
Feb-2025  98.55  97.74  98.07 106.76 105.88 106.25 20
Mar-2025 101.00 106.19 106.35 104.21 109.56 109.72 21
Apr-2025 104.64 100.89 100.80 103.05  99.36  99.27 22
May-2025 100.58 102.50 102.56  99.05 100.95 101.00 22
Jun-2025  98.86  98.45  98.27 102.00 101.57 101.39 21
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Last Update: March 15, 2024