FOR THUNDER AND HEAVY RAIN.
51. If long horizontal strips appear with two or three edges spreading out at top into feathers, and passing over the middle of other clouds, generally there will be thunder.
52. If the clouds be uniformly black, or dark gray.
53. In May and July it thunders most; in May, expect thunder with a south-west wind.
54. If there be north-east or easterly wind in the spring, after a strong increase of heat, and small clouds appear in different parts of the sky; or if the wind change from east to south at the appearance of clouds preceded by heat.
55. If a morning fog form into clouds, at different heights, which increase in size and drive in layers.
56. If clouds float at different heights and rates, but generally in opposite directions.
57. If there be many “falling stars” on a fine summer’s eve.
58. If there be sheet lightning, with a clear sky, on spring, summer, and autumn evenings.
59. If the wind be hushed with sudden heat.
60. If clover contract its leaves.
61. If there be thunder in the evening, there will be much rain and showery weather.