Speeds will normally be selected and posted for good weather conditions and dry pavement. Texas law, however, also provides for the posting of speeds for wet weather conditions.

Except in cases where the statewide maximum legal limits are posted, speeds will normally be posted on the basis of daylight speed values determined under good weather conditions.

When it can be shown that it is required during wet or inclement weather, a wet weather speed zone may be established by Transportation Commission minute order. The wet weather speed limit should be posted in addition to the regular posted speed zone. When appropriately signed, this wet weather speed limit will be effective during wet weather at any time during hours of daylight and darkness.