It's frequency of things, not existence of things.
Once (back when I was a HS jr, so early '76) went to school when it was below freezing outside. By 6th period realized I'd dressed--t-shirt/jeans/warm winter gear utterly wrong). Walked outside and thought, "Sweating. Ugh. What the hell? Sweating?" Was taking girlfriend to the Balto. county public library ... hey, nerd date ... that afternoon but it it was in the upper '80s, morning temp + 60? Baltimore doesn't do that kind of thing, 25 for the morning low and 85 for the afternoon high? Dude? But, hey, it did. At least my usual teen style at the time was better than my girlfriend's. She'd "layered" and had troubles. I was "jeans and t-shirt" with a AT&T linesman jacket and could just shed the jacket. (But I never sported the right image ... my jeans and Black Sabbath t said 'stoner' not 'G/T science nerd' ... Sadly, my two eyes aren't independently controlled., so I can't claim 'true' chameleonicity. Not like anybody was fooled.)
Another time, within the last 10 years--and not on the Chesapeake Bay but Just North of Houston--I got up in the morning for work and thought it balmy, but knew to get home quick. 70s in the a.m., as in 6 a.m., but in the afternoon winterized my dozens of cacti/succulents, frost-tolerant citrus, and 200 linear feet of mostly Brassica garden frost-tolerant veggies, because when I got home after school (high school, so 'work') it was in the 40s, spitting rain, and the low was to be in the low 20s and that's not 'frost.' It was cold, nasty, windy, and took to near sundown--when I was chipping ice off of thing as they were freezing over.
I hate spreading plastic sheeting when a front moves through. Front = wind. Sheeting + wind = "I hate life".
This kind of crap is a commonplace. The only issue is how common it is.
Last time as last/this winter. I cleaned up my back patio a month or two ago. Some seed-grown endangered cactus species were fine; not so cold hardy species didn't make it. When moving plants to shelter that last "morning warm, afternoon cold, night sub-freezing" day I overlooked them.
(Did find a new problem. An insect that relied on sucking for nutrients came in with my sheltered Ferocactus and Echinocactus spp. Parasite lived until I killed it; seedlings ... they fought & lost. Oh ... Common species.)
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