If warm, sunny weather inspires you to get hot and heavy, you may want to skip getting it on in the pool and save your nookie time for dry land. Although making sweet love in the water sounds sensual and natural, since you're wearing next to nothing already, it's not exactly the safest way to get it on.
Here's a mood killer for you: lake, river, ocean, and pond water contain bacteria, so getting intimate can introduce that bacteria into your vagina, which could put you at risk for infections that you don't want up there. Pool water is no better since it contains chlorine, which could irritate your lady business or disrupt the natural pH balance in your vagina, leading to a yeast infection. As for hot tubs, they're often not chlorinated enough, which means they're teeming with who knows what.
You may have heard that getting busy underwater will prevent sexually transmitted infections (STIs) or pregnancy, but this is far from true. As long as there is contact between two partners, semen and other bodily fluids can still pass from one person to another, which makes conception or contraction of STIs possible. You're using a condom, you say? Although in the bedroom condoms are very effective at preventing both pregnancy and the spread of infection, in the water, the lack of natural lubrication can make condoms more likely to break or slip off without either person realizing it — not to mention the lack of natural moisture can also cause friction, which will chafe your sensitive lady parts. Water and sex just don't mix, so the best advice is to reserve pool time for swimming, and save the shagging for later.