Official data, five years of history
Weather risk calendar for freight corridors
The National Weather Service reports go into the NOAA Storm Events database. Counting the days in each month on which at least one event was recorded in a state, over 5 years (2021 to 2025), shows when each corridor is exposed. Snow and ice peak in winter on the northern corridors, thunderstorms and flood in late spring and summer in the south and plains, and hurricanes in late summer on the Gulf and Atlantic. This is not a forecast and not a delay count.
Historical dataNOAA NCEI Storm Events Database (aggregates)Data period: calendar years 2021 to 2025Retrieved Oct 9, 2026, 11:04 UTCretrieved Oct 9, 2026
What event-days are
An event-day is a calendar day with at least one recorded event of that hazard group in the state. It depends on reporting as well as weather, covers the whole state (a long state has several climates), and says nothing about delays or closures. The corridor lists are the states each interstate passes through, put together by us from route maps; they do not follow county lines. The NWS alerts API returns only active alerts, so the NOAA archive is the official history source we could reach.
Winter exposure by state
Darker states have more days a year with a recorded snow, ice or freeze event. Click a state or a row.
- 2 days to 10 days (11 states)
- 11 days to 17 days (10 states)
- 18 days to 23 days (10 states)
- 24 days to 39 days (10 states)
- 41 days to 84 days (10 states)
- No data
| State | Winter days | Flood and heavy rain days | Wind and storm days | Tropical days | Fog and dust days | Heat and fire days | Winter peak month |
|---|---|---|---|---|---|---|---|
| Alabama | 11 | 32 | 78 | 1 | 0 | 15 | Jan |
| Alaska | 84 | 22 | 37 | 0 | 0 | 3 | Dec |
| Arizona | 16 | 51 | 69 | 0 | 21 | 85 | Feb |
| Arkansas | 10 | 56 | 60 | 0 | 0 | 27 | Jan |
| California | 68 | 71 | 108 | 1 | 55 | 50 | Mar |
| Colorado | 84 | 47 | 103 | 0 | 15 | 20 | Jan |
| Connecticut | 12 | 8 | 23 | 0 | 0 | 5 | Jan |
| Delaware | 6 | 9 | 15 | 0 | 5 | 3 | Jan |
| District of Columbia | 4 | 7 | 7 | 0 | 0 | 2 | Jan |
| Florida | 2 | 77 | 104 | 5 | 1 | 10 | Jan |
| Georgia | 4 | 33 | 77 | 2 | 0 | 2 | Jan |
| Hawaii | 2 | 32 | 6 | 1 | 0 | 4 | Apr |
| Idaho | 41 | 16 | 44 | 0 | 2 | 15 | Feb |
| Illinois | 23 | 51 | 72 | 0 | 10 | 11 | Jan |
| Indiana | 20 | 35 | 50 | 0 | 4 | 8 | Jan |
| Iowa | 20 | 29 | 63 | 0 | 1 | 6 | Jan |
| Kansas | 18 | 31 | 101 | 0 | 10 | 4 | Jan |
| Kentucky | 14 | 46 | 59 | 0 | 8 | 9 | Feb |
| Louisiana | 4 | 36 | 59 | 2 | 0 | 18 | Jan |
| Maine | 25 | 13 | 19 | 0 | 0 | 4 | Feb |
| Maryland | 28 | 33 | 40 | 1 | 4 | 4 | Jan |
| Massachusetts | 15 | 15 | 34 | 1 | 0 | 3 | Jan |
| Michigan | 46 | 13 | 46 | 0 | 0 | 2 | Jan |
| Minnesota | 43 | 17 | 59 | 0 | 1 | 6 | Feb |
| Mississippi | 5 | 30 | 67 | 1 | 0 | 24 | Jan |
| Missouri | 18 | 46 | 71 | 0 | 7 | 19 | Jan |
| Montana | 59 | 17 | 103 | 0 | 12 | 11 | Dec |
| Nebraska | 23 | 18 | 88 | 0 | 2 | 9 | Jan |
| Nevada | 39 | 25 | 88 | 0 | 5 | 21 | Mar |
| New Hampshire | 10 | 11 | 17 | 0 | 0 | 0 | Jan |
| New Jersey | 15 | 21 | 31 | 0 | 9 | 5 | Feb |
| New Mexico | 21 | 44 | 103 | 0 | 12 | 10 | Jan |
| New York | 42 | 31 | 58 | 0 | 0 | 11 | Jan |
| North Carolina | 13 | 40 | 76 | 2 | 0 | 2 | Jan |
| North Dakota | 21 | 8 | 53 | 0 | 1 | 0 | Feb |
| Ohio | 16 | 37 | 52 | 0 | 0 | 0 | Jan |
| Oklahoma | 11 | 26 | 95 | 0 | 1 | 48 | Feb |
| Oregon | 44 | 12 | 38 | 0 | 1 | 20 | Feb |
| Pennsylvania | 33 | 35 | 57 | 0 | 8 | 5 | Jan |
| Rhode Island | 2 | 5 | 11 | 0 | 0 | 0 | Feb |
| South Carolina | 4 | 22 | 67 | 3 | 0 | 2 | Jan |
| South Dakota | 37 | 26 | 89 | 0 | 2 | 10 | Feb |
| Tennessee | 19 | 35 | 69 | 0 | 0 | 19 | Jan |
| Texas | 17 | 76 | 168 | 1 | 6 | 71 | Jan |
| Utah | 37 | 32 | 62 | 0 | 5 | 6 | Mar |
| Vermont | 20 | 7 | 20 | 0 | 0 | 4 | Jan |
| Virginia | 24 | 54 | 72 | 1 | 2 | 3 | Jan |
| Washington | 38 | 15 | 25 | 0 | 2 | 25 | Dec |
| West Virginia | 31 | 37 | 51 | 0 | 2 | 2 | Jan |
| Wisconsin | 36 | 24 | 46 | 0 | 1 | 3 | Jan |
| Wyoming | 54 | 10 | 131 | 0 | 0 | 6 | Feb |
Days are averaged over 5 years. Groups: winter = snow, ice, freezing fog, frost and freeze, extreme cold; flood = flood, flash flood, heavy rain, coastal flood; wind = thunderstorm wind, high wind, tornado, hail; tropical = hurricane, tropical storm, storm surge; visibility = dense fog, dust, smoke; heat and fire = excessive heat, wildfire.
Corridor calendar
Pick a hazard to see how many event-days a month an interstate corridor passes through, on average across its states.
Snow, ice and freezing weather
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 8.2 | 9.1 | 7.1 | 5.6 | 2.1 | 1.8 | 0.0 | 0.2 | 0.7 | 2.6 | 4.3 | 8.3 |
| I-10 | 4.3 | 4.1 | 3.0 | 1.1 | 0.7 | 0.3 | 0.0 | 0.1 | 0.1 | 0.5 | 1.2 | 2.4 |
| I-35 | 6.4 | 6.2 | 2.5 | 0.9 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.6 | 1.4 | 3.2 |
| I-40 | 6.0 | 5.3 | 3.1 | 1.2 | 0.7 | 0.3 | 0.0 | 0.1 | 0.1 | 0.6 | 1.6 | 2.8 |
| I-70 | 8.5 | 6.4 | 3.6 | 2.2 | 0.9 | 0.0 | 0.0 | 0.0 | 0.1 | 1.4 | 2.8 | 4.9 |
| I-75 | 5.0 | 4.1 | 1.7 | 0.9 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.5 | 1.9 | 2.6 |
| I-80 | 7.3 | 6.7 | 4.8 | 2.1 | 0.9 | 0.2 | 0.0 | 0.1 | 0.1 | 1.4 | 2.7 | 5.2 |
| I-81 | 9.5 | 6.6 | 2.8 | 1.1 | 0.6 | 0.0 | 0.0 | 0.0 | 0.0 | 0.2 | 2.8 | 5.7 |
| I-90 | 8.2 | 7.7 | 4.3 | 2.6 | 0.6 | 0.1 | 0.0 | 0.0 | 0.1 | 1.1 | 3.2 | 7.0 |
| I-94 | 8.1 | 8.2 | 4.2 | 2.5 | 0.5 | 0.1 | 0.0 | 0.0 | 0.1 | 1.1 | 3.3 | 7.0 |
| I-95 | 5.1 | 3.6 | 1.4 | 0.5 | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 1.1 | 2.8 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
Floods and heavy rain
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 4.3 | 3.0 | 3.5 | 0.7 | 1.9 | 2.1 | 3.0 | 3.3 | 2.7 | 1.3 | 3.0 | 4.1 |
| I-10 | 2.0 | 1.8 | 3.2 | 2.9 | 4.9 | 6.7 | 9.3 | 8.7 | 6.0 | 2.7 | 1.9 | 2.0 |
| I-35 | 0.8 | 0.5 | 1.7 | 4.3 | 7.0 | 7.1 | 6.4 | 4.5 | 2.3 | 1.2 | 1.0 | 0.5 |
| I-40 | 2.2 | 2.0 | 3.3 | 3.0 | 5.7 | 5.8 | 9.3 | 7.8 | 4.6 | 2.2 | 1.7 | 2.1 |
| I-70 | 1.3 | 1.8 | 2.1 | 2.9 | 4.9 | 5.7 | 8.3 | 6.8 | 2.6 | 1.0 | 0.4 | 0.6 |
| I-75 | 1.3 | 2.5 | 2.3 | 3.0 | 3.7 | 5.7 | 7.0 | 7.1 | 4.2 | 1.8 | 0.7 | 0.8 |
| I-80 | 1.4 | 1.8 | 2.2 | 2.2 | 2.9 | 4.4 | 6.8 | 5.6 | 2.6 | 1.1 | 0.8 | 1.3 |
| I-81 | 1.2 | 1.9 | 1.6 | 1.6 | 4.0 | 5.0 | 8.4 | 6.7 | 4.1 | 1.5 | 0.4 | 1.0 |
| I-90 | 1.0 | 1.2 | 1.3 | 2.3 | 2.7 | 4.5 | 5.3 | 4.2 | 1.4 | 0.6 | 0.4 | 0.6 |
| I-94 | 0.7 | 1.2 | 1.6 | 3.0 | 2.4 | 4.3 | 5.1 | 3.5 | 0.9 | 0.4 | 0.1 | 0.3 |
| I-95 | 0.9 | 0.6 | 1.0 | 1.1 | 2.1 | 3.3 | 5.8 | 4.6 | 3.5 | 1.7 | 0.6 | 0.8 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
Thunderstorm wind, high wind, tornado, hail
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 6.5 | 5.3 | 7.3 | 4.5 | 4.7 | 3.7 | 3.1 | 3.6 | 2.5 | 3.7 | 5.7 | 6.4 |
| I-10 | 5.3 | 4.8 | 8.7 | 8.9 | 12.8 | 13.1 | 11.7 | 10.5 | 6.2 | 4.2 | 3.5 | 4.8 |
| I-35 | 2.9 | 2.7 | 6.7 | 10.0 | 14.4 | 15.0 | 13.6 | 10.8 | 7.1 | 3.9 | 2.7 | 3.2 |
| I-40 | 5.2 | 5.0 | 8.2 | 9.2 | 12.8 | 11.9 | 12.2 | 10.2 | 6.7 | 4.0 | 3.6 | 4.7 |
| I-70 | 1.4 | 2.3 | 4.9 | 5.6 | 8.8 | 10.4 | 12.8 | 9.1 | 4.5 | 2.4 | 1.2 | 2.4 |
| I-75 | 1.9 | 2.5 | 5.3 | 6.1 | 8.8 | 11.1 | 12.4 | 9.6 | 4.7 | 2.0 | 1.3 | 2.3 |
| I-80 | 3.5 | 4.5 | 6.1 | 5.8 | 7.9 | 9.4 | 11.9 | 8.2 | 4.6 | 3.1 | 3.2 | 4.8 |
| I-81 | 1.7 | 2.5 | 4.3 | 4.1 | 6.5 | 8.8 | 12.6 | 8.4 | 4.1 | 1.3 | 1.3 | 2.3 |
| I-90 | 2.8 | 3.3 | 3.9 | 4.4 | 6.5 | 9.2 | 11.8 | 7.9 | 4.1 | 2.4 | 2.9 | 4.1 |
| I-94 | 1.8 | 2.6 | 3.3 | 4.3 | 6.6 | 10.4 | 12.6 | 8.3 | 3.9 | 2.4 | 2.5 | 2.8 |
| I-95 | 1.4 | 1.4 | 3.0 | 3.2 | 5.0 | 7.1 | 10.1 | 6.6 | 3.0 | 1.1 | 0.8 | 1.6 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
Hurricanes and tropical storms
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.0 | 0.0 | 0.1 | 0.1 | 0.0 | 0.0 | 0.0 |
| I-10 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.3 | 0.1 | 0.5 | 0.4 | 0.1 | 0.1 | 0.0 |
| I-35 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.0 | 0.1 | 0.1 | 0.0 | 0.0 | 0.0 |
| I-40 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.1 | 0.2 | 0.2 | 0.0 | 0.0 | 0.0 |
| I-70 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| I-75 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.1 | 0.4 | 0.3 | 0.1 | 0.2 | 0.0 |
| I-80 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| I-81 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.1 | 0.1 | 0.0 | 0.0 | 0.0 |
| I-90 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| I-94 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| I-95 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.2 | 0.3 | 0.3 | 0.1 | 0.1 | 0.0 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
Dense fog, dust and smoke
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 5.1 | 2.3 | 0.3 | 0.8 | 0.2 | 0.1 | 0.3 | 0.9 | 0.6 | 1.3 | 2.6 | 4.5 |
| I-10 | 2.0 | 1.2 | 0.7 | 0.7 | 0.4 | 0.6 | 0.9 | 1.1 | 0.6 | 0.6 | 1.0 | 1.9 |
| I-35 | 0.6 | 0.2 | 0.5 | 0.9 | 0.5 | 0.2 | 0.2 | 0.0 | 0.1 | 0.2 | 0.6 | 0.6 |
| I-40 | 2.1 | 1.2 | 0.7 | 0.7 | 0.4 | 0.6 | 0.9 | 1.1 | 0.6 | 0.6 | 1.0 | 1.9 |
| I-70 | 0.8 | 0.4 | 0.4 | 0.9 | 0.8 | 0.2 | 0.3 | 0.2 | 0.2 | 0.4 | 0.8 | 1.3 |
| I-75 | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | 0.1 | 0.1 | 0.1 | 0.1 | 0.0 | 0.4 | 0.2 |
| I-80 | 1.8 | 0.8 | 0.3 | 0.6 | 0.6 | 0.2 | 0.3 | 0.5 | 0.3 | 0.6 | 1.1 | 1.9 |
| I-81 | 0.4 | 0.2 | 0.2 | 0.2 | 0.3 | 0.0 | 0.0 | 0.2 | 0.2 | 0.3 | 0.1 | 0.4 |
| I-90 | 0.7 | 0.1 | 0.3 | 0.3 | 0.4 | 0.1 | 0.1 | 0.1 | 0.2 | 0.1 | 0.4 | 0.4 |
| I-94 | 1.1 | 0.1 | 0.5 | 0.3 | 0.4 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.7 | 0.5 |
| I-95 | 0.2 | 0.2 | 0.1 | 0.2 | 0.2 | 0.0 | 0.1 | 0.1 | 0.1 | 0.2 | 0.1 | 0.3 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
Excessive heat and wildfire
| Corridor | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| I-5 | 0.5 | 0.3 | 0.5 | 0.7 | 1.7 | 5.1 | 8.3 | 6.9 | 4.3 | 1.9 | 0.7 | 0.7 |
| I-10 | 0.3 | 0.6 | 1.3 | 1.6 | 2.7 | 6.8 | 9.3 | 8.5 | 2.8 | 0.9 | 0.3 | 0.2 |
| I-35 | 0.3 | 1.0 | 2.7 | 1.4 | 0.8 | 3.6 | 6.9 | 6.4 | 1.3 | 0.8 | 0.2 | 0.5 |
| I-40 | 0.4 | 0.8 | 1.9 | 1.9 | 2.4 | 7.5 | 10.4 | 8.8 | 3.0 | 1.1 | 0.4 | 0.4 |
| I-70 | 0.0 | 0.0 | 0.4 | 0.3 | 0.1 | 1.3 | 3.0 | 1.8 | 0.2 | 0.4 | 0.2 | 0.1 |
| I-75 | 0.0 | 0.1 | 0.2 | 0.2 | 0.5 | 1.1 | 2.7 | 2.0 | 0.1 | 0.1 | 0.1 | 0.0 |
| I-80 | 0.2 | 0.1 | 0.2 | 0.5 | 0.4 | 2.2 | 3.5 | 2.5 | 1.1 | 0.6 | 0.3 | 0.1 |
| I-81 | 0.0 | 0.0 | 0.1 | 0.1 | 0.0 | 1.6 | 3.4 | 1.7 | 0.1 | 0.0 | 0.2 | 0.0 |
| I-90 | 0.0 | 0.0 | 0.2 | 0.2 | 0.1 | 1.3 | 3.0 | 2.3 | 0.9 | 0.4 | 0.2 | 0.2 |
| I-94 | 0.0 | 0.0 | 0.1 | 0.1 | 0.1 | 0.9 | 2.0 | 1.7 | 0.5 | 0.3 | 0.1 | 0.0 |
| I-95 | 0.0 | 0.0 | 0.1 | 0.2 | 0.2 | 0.8 | 1.4 | 0.8 | 0.0 | 0.0 | 0.1 | 0.0 |
Each cell is the average, over the states on the corridor, of event-days per month for this hazard group (mean of 5 years). Darker = more.
What this number means
- Event-days are exposure, not delay. A day with a recorded thunderstorm somewhere in a state does not close its highways.
- The averages hide the worst day. The calendar shows the typical month. The worst-state column in the calculator shows the hottest spot on the route.
- Different hazards peak in different months and places, so a corridor can be safe in one season and exposed in another.
- Five years is short for rare events like hurricanes. A quiet month here is not a guarantee.
What to do about it
- Look at the months you run each corridor, and build slack into the schedule in the dark cells.
- Check the corridor on the day of travel in the NWS forecast, which this page is not.
- Keep chains and winter gear on board in the northern corridors from the first dark cell, not the first storm.
- Count weather days in your own load log for a year. That makes the cost below your number, not the average.
What weather days cost on a corridor
Pick a corridor, a month and a hazard. You supply how often your trucks actually lose time on such a day.
Expected weather cost that month
enter numbers
- States on the corridor
- Average event-days that month
- Worst state on the route
- Cost if the worst state applied
Formula: trucks x average event-days x share x hours x cost per hour. Event-days are exposure, not delay. The example numbers are invented placeholders. Replace them with yours.
Where the numbers come from
See what your last 20 loads show.
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