Allen fought villains like Captain Cold, the Weather Wizard, and Heatwave. The reason they were so successful against him was that Allen's powers were weak to extreme heat and cold.
Wally's only "unique" weakness is to excessive cold. This doesn't extend to simple weather conditions, as only devices such as Captain Cold's absolute zero Cold Gun have been enough to slow the speedster down enough to make him vulnerable.
Like all speedsters, Bart is susceptible to cold temperatures. He was also at the mercy of his fast metabolism in his early appearances, which acted as an illness that forced his body to age.
The Flash is arguably the fastest being in the multiverse because of the array of powers the speed force gives him. His weakness is cold temperature because his molecules cannot vibrate at their normal speed if the cold slows them down.
Doctor Strange is a Master of the Mystic Arts who wields a number of powerful spells and artifacts, making him a dangerous threat. Beating the Flash as simple as Doctor Strange moving the battlefield to another dimension or changing into one of his more powerful forms.
Why EVERY Villain is Terrified of the Flash (Even Joker)
Who is the slowest flash in flash?
9 Jay Garrick
Garrick became one of the elder statesmen of the DC Universe, a member of the Justice Society, and an all around role model. His years of experience made him a great hero, but speed wise, Jay is the slowest Flash.
Weaknesses. Magical Vulnerability: Only significant magic can affect him. Lightning: Lightning attacks that cause damage and can cause Black Adam to revert back to Theo Adam.
But while Wally is now on record as being technically faster than Barry, by his own words, Bart will eventually become faster than he is, and is pretty close to it now. We know it's controversial not putting Barry in the number two slot.
Instead, Flash fears the hyper-intelligent, telepathic gorilla he's had occasional bouts with. The core of the nightmare seems to be centered around Barry failing Wally, suggesting that Gorilla Grodd is the villain that Flash fears when it comes to the safety of his extended family.
Batman is easily overpowered, unable to even land a hit due to Reverse-Flash phasing through any attacks, but Batman points out that if Reverse-Flash is standing on the physical ground, then not all of his body must be phasing.
At base levels — i.e. the levels of power that Wally and Superman have both showed when it comes to foot speed — Wally would take the race. With Superman's newly enhanced power, he'd likely win. But if there were no rules against how Wally used the Speed Force, then Wally would win.
Naturally, Superman is much stronger overall. But moving at his highest speeds, Barry can punch Superman with enough force to knock him back through walls. He has greater strength than most heroes, simply because of his ability to transfer speed into energy.
Shazam's greatest weakness is mind control, which turns him into a living weapon with no one to stop him. This weakness harms others more than Shazam himself, as he is physically invulnerable. If a villain gains control of Shazam, he becomes the deadliest member of the Justice League.
However, his background was later retconned to reveal that he is actually the Aboriginal (Kunwinjku) deity known as Mamaragan. According to this retcon, Mamaragan's songlines guided him to a seat on the Council of Eternity, where he adopted the title of "Wizard" and later Shazam.
Love made to last. Artemis and Kid Flash are both former members of the Team, but from different backgrounds. He comes from a legacy of heroes, while her family consists only of criminals.
Despite Nora and Bart representing the next generation of speedsters, Barry is still way faster than both of them, and it boils down to a few key factors. Nora and Bart are younger than Barry, and likely have less overall experience with the Speed Force.
He became the Red Death, who was a vicious speedster capable of outpacing even the Flash. The Barry Allen of the main world fought the Red Death several times and was seemingly beaten every round.
