What with changes in climate and available forage, are you noticing changes in when your bees start to swarm? Are your swarm start dates changing? If yes why do you think?
Strong hive weaker hive?
Number of warm days?
Long wet winter / other abnormal conditions?
Average night temperatures?
Number of weeks of forage?
Send your 1) old vs new date changes 2) theories as to why and 3) your zip code if you would.
Brian of LiveHoneybees