Hazardous Conditions — ruling 1

Hazardous Conditions doesn't care what kind of counter a creature has on it. Whether +1/+1, -1/-1, charge, or fate, any kind of counter causes a creature to be unaffected.

Hazardous Conditions — ruling 2

The set of creatures affected by Hazardous Conditions is determined as the spell resolves. Creatures that get a counter later in the turn will continue to get -2/-2. Creatures that enter the battlefield or lose their counters later in the turn and noncreature permanents that become creatures later in the turn won't get -2/-2.

Hazardous Conditions : règles, fonctionnement et interactions (MTG)

Hazardous Conditions is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Creatures with no counters on them get -2/-2 until end of turn.

How it works : Hazardous Conditions

Original English text — Wizards of the Coast / Scryfall

#1September 20, 2016· Wizards of the Coast
Hazardous Conditions doesn't care what kind of counter a creature has on it. Whether +1/+1, -1/-1, charge, or fate, any kind of counter causes a creature to be unaffected.
No other card is named in this ruling.
#2September 20, 2016· Wizards of the Coast
The set of creatures affected by Hazardous Conditions is determined as the spell resolves. Creatures that get a counter later in the turn will continue to get -2/-2. Creatures that enter the battlefield or lose their counters later in the turn and noncreature permanents that become creatures later in the turn won't get -2/-2.
No other card is named in this ruling.