How long a car battery lasts depends a lot on where you drive. AAA says batteries may last five years or longer in cooler northern climates, while around three years is more typical in southern locales.
Enter your ZIP code to see how hot it gets where you live, how long a battery typically lasts in that climate, and when to have yours tested.
The calculator on this page takes a 5-digit ZIP code, and the battery's age if you know it, and returns the estimate for your area.
The same estimate for big cities across the country, from the highest heat score to the lowest. Each row uses the 3-digit ZIP prefix shown, which can cover more than the city itself.
| City | ZIP prefix | Heat score (cooling degree days a year) | Days a year above 90F | Typical battery life (our estimate) |
|---|---|---|---|---|
| San Juan, PR | 009 | 6,201 | 54 | about 3 years |
| Honolulu, HI | 968 | 5,051 | 10 | about 3 years |
| Miami, FL | 331 | 4,922 | 85 | about 3 years |
| Phoenix, AZ | 850 | 4,580 | 169 | about 3 years |
| Las Vegas, NV | 891 | 3,695 | 134 | about 3 years |
| Houston, TX | 770 | 3,663 | 104 | about 3 years |
| Dallas, TX | 752 | 3,174 | 108 | about 3 years |
| Atlanta, GA | 303 | 2,116 | 52 | about 3.5 to 4.5 years |
| New York, NY | 100 | 1,377 | 15 | about 4 to 5 years |
| Los Angeles, CA | 900 | 1,228 | 15 | about 4 to 5 years |
| Chicago, IL | 606 | 1,147 | 9 | about 4 to 5 years |
| Boston, MA | 021 | 1,018 | 16 | about 4 to 5 years |
| Denver, CO | 802 | 1,005 | 51 | about 4 to 5 years |
| Minneapolis, MN | 554 | 856 | 10 | 5 years or more |
| Seattle, WA | 980 | 232 | 3 | 5 years or more |
Climate. We took one point for each 3-digit ZIP prefix: the average location of the ZIP code areas that start with those digits (U.S. Census Bureau 2025 ZIP Code Tabulation Area centers). For each year from 2016 to 2025 we took three numbers from NOAA's Applied Climate Information System (ACIS) and its PRISM daily temperature grid, then averaged the 10 years: cooling degree days (for each day, how many degrees its average temperature is above 65F, added up over the year), the days the high topped 90F, and the nights the low fell below 32F. The page shows whole numbers.
Outside the contiguous states. The PRISM grid covers only the contiguous states. For Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands each ZIP prefix uses one NOAA airport weather station instead (western Puerto Rico uses San Juan's, because the Aguadilla station has too few complete years). Guam has no estimate yet.
Battery life. AAA says: "Batteries may last five years or longer in cooler northern climates, while in southern locales, around three years is more typical." Consumer Reports, citing AAA data, puts battery life at "58 months or longer in the farthest northern regions of the U.S. to less than 41 months in the most southern regions."
Our estimate. We spread that north-to-south range across the heat score (cooling degree days a year) in the four steps below. We use it rather than days above 90F because humid and tropical places stay warm for most of the year without many 90F days; days above 90F is shown because it is easier to picture. The steps are our own estimate, not figures AAA or Consumer Reports gives for any ZIP code, and an individual battery can wear out sooner or later.
| Heat score (cooling degree days a year) | Typical battery life (our estimate) |
|---|---|
| Under 1,000 | 5 years or more |
| 1,000 to 1,999 | about 4 to 5 years |
| 2,000 to 2,999 | about 3.5 to 4.5 years |
| 3,000 or more | about 3 years |
Testing. AAA: "After three years, test the battery yearly." Consumer Reports recommends a load test "annually after it's 2 years old." Where the heat score is 2,000 cooling degree days a year or more we suggest the earlier, Consumer Reports schedule; everywhere else, AAA's.
Limits. A 3-digit ZIP prefix can cover a large area with hotter and cooler parts, and the numbers are gridded estimates (or, outside the contiguous states, one airport station) rather than readings at your address. Treat the result as a planning guide, and test the battery on schedule.
AAA says batteries may last five years or longer in cooler northern climates, while around three years is more typical in southern locales. Consumer Reports, citing AAA data, puts it at "58 months or longer in the farthest northern regions of the U.S. to less than 41 months in the most southern regions." Our estimate for a ZIP code comes from its heat score, the cooling degree days a year (how much and how long it is warm there): 5 years or more where that is under 1,000, and about 3 years where it is 3,000 or more.
Heat. Consumer Reports says: "Summer heat is tougher on car batteries than winter's chill." Cold does not wear a battery out as fast as heat does, but a cold morning is when a weak battery fails to start the car, so where winters are hard it is worth having an older battery tested before the first freeze.
AAA says to test the battery yearly after three years. Consumer Reports recommends a load test annually after the battery is 2 years old. Where the heat score is 2,000 cooling degree days a year or more (the calculator on this page shows yours), follow the earlier, Consumer Reports schedule; otherwise AAA's.
We take a heat score for the middle of your 3-digit ZIP prefix: the cooling degree days a year, which adds up, for every day, how many degrees its average temperature is above 65F. It comes from NOAA temperature data averaged over recent years (the years are shown with each result), so warm, humid places score high even when few days top 90F. We place the score on a four-step scale built from the AAA and Consumer Reports figures above. The steps are our own estimate, not a measurement of your battery, so use the result to decide when to test it rather than when it will fail.
ANCEL BA101 Car Battery Tester - A 12-volt battery and charging system tester, for checking your battery between shop visits.
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