

Yellowing and bronzing of leaves are symptoms associated with a light freeze for a short duration of 1-2 hours. The damage can be much more significant for a hard freeze and in the presence of frost.

The underside of the tomato leaves may also shows bronzing symptoms. This would be very uniform especially to the outer and fully exposed sections of the field.
COLD INJURY
Cause: Temperatures of 28-32 F or below with or without frost
Tomato diseases