TQ wrote:

.........................
I/ve always held off setting mine outside until the average low temperature
is 55°F (13°C) or higher...........................


Well, I envy you. Where I live the average low temperature during the
warmest part of July is 52 degrees.
I try to plant them out the first week of June even though we usually
have our last snow flurry the first week of May. This year was no
exception. We had snow on May 2,3 and 4. Enough to make the ground white
for a while on the 3rd. A week later on the 10th it was 81 degrees and
my daughter took a brief swim in the lake. Then on the 12th it was in
the teens at sunrise. Crazy.
Yeah, I do grow tomatoes.

Steve (in the Adirondacks)