Exterior painting should be done before landscaping or putting down multch, which will just get trampled if you paint later on.
Get your painting done before other distractions' (like gardening, sports and barbecues) begin.
DON'T PUT OFF REPAINTING
If won't take long for exposed wood to begin to rot, and other types of exteriors also suffer when the paint wears off. If you wait too long, your home may develop bigger problems which will need to be addressed before repainting.
Exterior latex paint forms the most durable, protective finish when the weather is mild. It's always best to do exterior painting when the temperature is above 50°F, but not too hot. Very hot days can cause the paint to dry too quickly. By painting in moderate weather, you will get a longer-lasting paint job.