The temperature range typical of summer water (without heat pollution) is—

• a$5\text{-}10^\circ\mathrm{C}$
• b$15\text{-}20^\circ\mathrm{C}$
• c$30\text{-}35^\circ\mathrm{C}$ (occasionally up to $40^\circ\mathrm{C}$)
• d$50\text{-}60^\circ\mathrm{C}$