Yes, you should be very careful with your child during summer and all climatic changes.
Always use cotton clothes/dresses, both at home and while going out.
Try to avoid diapers at home, since it may cause irritations and rashes. You can use them, while you take the child outside. At home, you can use cotton underwear and let them be not tight fitting
While you make to lie them, do not make the child lie straight over the plastic or rubber sheet. Cover the bed with old cotton saree or dhothi, and then leave the child over it..
Give lot of fluids, especially water. You can give vegetable soups,ie., cook the vegetables with water, drain the water and give this water.Later, you can mash those vegetables and give them directly.You can give fruit juices.
Always use, well filtered, boiled water for all the uses of child's intake. This will avoid all kinds of diseases.
Now, the child would have started moving. So, keep its surroundings very clean, since, the child would put each and everything in its mouth. Always be monitoring the child.