NOAA Billion dollar disasters: https://www.ncdc.noaa.gov/billions/
Peak flooding is June and July:
Peak hurricane season is September and usually runs 1 June to 30 November:
Tornado season usually refers to the time of year the U.S. sees the most tornadoes. The peak “tornado season” for the southern Plains (e.g., Texas, Oklahoma, and Kansas) is from May into early June. On the Gulf coast, it is earlier in the spring. In the northern Plains and upper Midwest (North and South Dakota, Nebraska, Iowa, Minnesota), tornado season is in June or July. But, remember, tornadoes can happen at any time of year. Tornadoes can also happen at any time of day or night, but most tornadoes occur between 4–9 p.m.NOAA
Note that Tornados can extend into southern Canada. Information on fatality trends here.
Information on Tornado Alley via NOAA.
There is a “second season” of tornadoes in September thru October.
Blizzards have been reported in all months except July, August, and September. Monthly blizzard occurrence highlighted a more active blizzard season (December, January, February, and March; Fig. 6) and a less active blizzard period during the transitional seasons (October, November, April, and May; Fig. 7).