Rainy weather can create great photo opportunities. Good subjects include:

• close-up details like leaves, rocks, flowers, and plants with raindrops on them
• dramatic skies and storm clouds
• portraits lit by overcast light, since clouds act like a large soft diffuser
• urban scenes with people, umbrellas, wet streets, and splashing through puddles
• puddles and other reflective surfaces for reflections
• familiar landmarks or buildings photographed in unusual weather like rain, fog, or storms

A few technique ideas also help:

• If the sky is dull, compose to exclude it.
• If the sky is dramatic, use it as a background by shooting upward.
• A little fill flash on nearby subjects can make them stand out and make the sky look darker and more dramatic.
• Adjust white balance or use warming filtration if the scene feels too cool.

In short, rain adds texture, mood, reflections, and a less-seen version of everyday scenes.