The high temperatures of summer can cause heat exhaustion or even heat stroke. Avoid strenuous activities during the day. Drink plenty of water, even when you are not thirsty; your body can lose large amounts of water without you realizing it.
Wildlife: Rattlesnakes, one type of scorpion, and the Gila monster are poisonous, but will leave you alone unless disturbed or cornered. Wear sturdy boots and watch where you step.
Amoeba: A microscopic amoeba, Naegleria fowleri, which can live in hot springs, can cause a rare infection and sometimes death. Do not dive or submerse your head in warm springs or associated streams.
Plants: Oleander is a toxic plant common to developed areas; neither you nor your pet should eat any plant part or drink water from ditches near the oleander.