You all have been very helpful in regard to my questions about getting a new job, but I have just one more. I did get a job in another district for next year, and the contract has been signed. Now I just need to inform my current district that I will not be returning. Our official deadline to do this is in July. Would it be more appropriate to wait until then, sometime around the last week of school, or should I let my district know ASAP? I feel like it would be more professional to let them know ASAP so that they can prepare longer to hire someone to fill my current position, but could there be any "politics" that would make doing this a bad idea?
If you want a good lasting relationship with the school, it would be best to let them know sooner verses later for the reasons you described. You might want to talk with the principal or a union leader 1-1, depending on your comfort. One thing to keep in mind is that the school might not want to invest more in you after letting them know (which is understandable).
Personally, I would let them know now. I would want to allow them the most time possible to find a suitable candidate. If you are more comfortable, maybe at the end of April. Once May hits, the year flies by.
My assumption on this statement: Example: Maybe there is a conference or training in May that your school thinks you would benefit from. They won't send you now.
I think it depends on your admin. I know some get mean/resentful. If that's the case, I wouldn't tell. Otherwise, I'd let them know ASAP.
My thoughts in that statement are that if there is a workshop or training that you want to go to they may not let you unless you use one of your personal days. Also, if they would have paid for it previously, they may not pay for it now. If they were going to send you to a training later in the year they may change their minds about it.
If you have signed a contract with the other district, you need to resign immediately. Principals need time to find someone new. If you wait, then many of the higher quality applicants will have found jobs elsewhere.
Once signed contract is in hand, you should resign quickly. If I am offered a job with contract, I will resign within a week. My only question is what about the school that does the post-hire check. In other words your contract is contingent on passing the background check. One school around here does that. Another school only does the criminal background check. No problems there.