Forecasts of the weather expected during the ensuing thirty-six hours are issued by the United States Weather Bureau daily at about 10 a.m. and 10 p.m. and are distributed to all parts of the country by telegraph, telephone, mail, and by means of flag and whistle signals.

Nearly all telephone companies cooperate or are willing to cooperate with the Weather Bureau in making the information available to the public in general. It is thus possible to obtain the official weather forecast by calling the central exchange of almost any telephone one may be using.

Signals of the United States Weather Bureau.

Flag Signals (Fig. 2)

United States Flag Signals

Fig. 2. — United States flag signals.

No. 1, square white flag, alone, indicates fair weather, stationary temperature.

No. 2, square blue flag, alone, indicates rain or snow, stationary temperature.

No. 3, square, white above, blue below, alone, indicates local rain, stationary temperature.

No. 4, triangular black, refers to temperature.

No. 5, square white, with black center, cold wave.

No. 1, with No. 4 above it, indicates fair weather, warmer.

No. 1, with No. 4 below it, indicates fair weather, colder.

No. 2, with No. 4 above it, indicates warmer weather, rain or snow.

No. 2, with No. 4 below it, indicates colder weather, rain or snow.

No. 3, with No. 4 above it, indicates warmer weather with local rains.

No. 3, with No. 4 below it, indicates colder weather with local rains.

No. 1, with No. 5 below it, indicates fair weather, cold wave.

No. 2, with No. 5 below it, indicates wet weather, cold wave.