It's upsetting when a toddler is being bitten or biting in day care, however it is to be expected. That being said, I think you need to be concerned about your center. Here's why:
1. It is never too hot for children to have some outside play time. I have a family child care, and we went outside every day in August. A couple times some of the children began to look flushed and tired, at which point we went inside, but most days I helped them stay cool by having water activities like running in the sprinkler, the wading pool, or at least splashing in the water table. I used to teach in a preschool, and we never kept the kids in due to heat. That was in Texas, and believe me, it was hotter there than here. On days when we had to stay in because of rain, we had a big room where we took all the balls and riding toys, because children have to have time to run around every day.
2. Five bites in six weeks is beyond excessive. By the time a child has suffered two bites, the staff should have a very proactive attitude. The director should have solutions - not excuses. When at my preschool we had one biter in the three year-old room, we realized after two incidents that it was occuring just before lunch, and moved lunch to an earlier time. When it happened in the toddler room, it was over a favorite toy, so we bought duplicates of that toy.
3. If a child has been bit three times in one day, you have a supervision issue with your care provider. S/he is not paying close enough attention or intervening appropriately.
If you are committed to that center, then prompt the director with questions about the incidents, so that you can determine a cause and help her correct the problem. You say, though, that the next class up has multiple biters. That tells me that there is an endemic problem throughout the center. Biting should not be a big problem in the twos class or older. I taught a class of ten two year-olds, and had two biting incidents in one year. We had one biter with two incidents in the three year-old class and that is it.
As with most things, you get what you pay for with child care. If you are paying at least $140 a week, you can get better care elsewhere. If not, you may want to consider increasing your budget for child care. The early childhood years are crucial to good development. Ninety-percent of brain development happens in the first five years. Paying more now will pay for itself when you have fewer behavior problems with your child over the years and he is ready for school with good self-esteem and a love of learning.
Good luck
C. at Loving Hands Family Child Care