Halloween weather changes by hour—and by place

One date · Very different local forecasts

Current NWS office updates show why the address and hour matter

Official local outlooks available Thursday afternoon describe different planning problems for Saturday evening. They are examples—not a nationwide forecast and not a substitute for the newest point forecast.

Houston and Galveston area

NWS Houston/Galveston highlights a hot Halloween, a daytime shower or thunderstorm chance, and lower rain chances into the evening. The hourly temperature still matters after the daytime rain chance decreases.

Middle Tennessee

NWS Nashville says Halloween starts dry, with showers developing late in the evening and higher rain chances overnight. The start and return times can therefore lead to different decisions.

Central Alabama

NWS Birmingham says some showers may be around Halloween evening, while more widespread showers should hold off until overnight. That timing difference is a reason to keep checking—not to treat an early forecast as a promise.

Hourly planning · Follow the full outing

Check the return hour, not only the departure hour

A dry start can become a wet return, and a mild afternoon can cool quickly after sunset. Open every hour from the first person leaving until the last person is expected home.

Compare air temperature, precipitation chance, wind speed and gusts, and the written weather description. If wind chill is shown, remember that NWS defines it for air temperatures at or below 50°F and wind above 3 mph; it describes heat loss from exposed skin, not the temperature of pavement, cars, or pipes.

Rain chance answers whether measurable precipitation is expected at the forecast point during the stated period. It does not say how long rain will last, how hard it will fall, or whether every street will be wet. Use the hourly wording and radar as separate pieces of the plan.

Lightning · Shelter before the storm arrives

If you hear thunder, move indoors

NWS says no place outside is safe when thunderstorms are in the area. A substantial building or an enclosed, metal-topped vehicle with the windows up is the safer destination.

A porch, small rain shelter, open-sided structure, or isolated tree is not safe lightning shelter. Plan the route to a safe building or vehicle before the outing begins. Once inside, wait at least 30 minutes after the last thunder before resuming outdoor activity.

Do not wait for rain. Lightning can be a threat before heavy precipitation reaches the location, and radar cannot replace the instruction to act when thunder is heard.

Official products · Different decisions

An outlook, forecast, watch, and warning are not interchangeable

Outlook

A broad early-planning product showing that a hazardous event may develop. It is not proof that a particular address will be affected.

Forecast

The expected temperature, rain, wind, or thunderstorm timing for a stated place and period. Forecasts change as new data arrives and do not themselves mean a warning is in effect.

Watch

The risk of a hazardous event has increased, but occurrence, location, or timing remains uncertain. Be ready to move or shorten the plan.

Warning

A hazardous event is occurring or has a very high probability of occurring in the warned area. Take the protective action in the warning rather than relying on an older forecast.