The four numbers worth writing down
A chameleon lives in a vertical climate, so one thermometer reading tells you very little. Log four things. First, the basking spot temperature where the chameleon actually sits to warm up, measured at branch height under the lamp. Second, the cooler ambient temperature low in the enclosure, where it retreats to cool down — the gap between the two is what lets it regulate itself. Third, the night-time temperature after lights-out, since most chameleons need a genuine drop overnight. Fourth, humidity at two moments: the peak just after misting, and the low point just before the next misting is due. That swing, wet to dry and back, is what the animal experiences, and it matters more than any single average.
Where and when to measure
Readings only compare honestly if they are taken the same way every time. Fix the probes or use a hand-held infrared thermometer on the same spots: the basking branch, a shaded lower branch, and mid-enclosure for humidity. Note the time with each set — a basking spot measured before the lamp has warmed up looks falsely cold, and humidity read during misting looks falsely perfect. Most keepers take a morning set once the lights have been on a while and an evening set before lights-out, with the night reading checked occasionally rather than nightly. Write the numbers down there and then; readings kept in your head are readings lost.
What to add beside the numbers
A column of temperatures means more with a few words attached. Note when a bulb or tube was replaced, when the misting duration or schedule changed, and when the enclosure moved rooms or the household heating came on — room conditions drive enclosure conditions, especially in screen enclosures. Add brief observations about the chameleon itself: drinking eagerly or ignoring droplets, eating well or refusing, eyes bright or sunken-looking, and the colour of its droppings' white portion, which reflects hydration. Those notes turn a puzzling dip in the log into an explained one.
Reviewing: a weekly skim, a monthly read
Skim the log once a week with one question in mind: is anything drifting? A basking spot creeping down usually means a lamp ageing; humidity lows sinking week by week point to misting that no longer matches a drier house. Sit down with it properly once a month, compare against the ranges your species needs — a veiled chameleon's comfortable humidity differs from a panther chameleon's — and adjust one thing at a time, then watch the log to see the effect. Review immediately, whatever the calendar says, if the chameleon stops eating, keeps its eyes closed in the day, or the readings jump suddenly; take the log itself to any vet visit, because weeks of dated numbers tell a vet more in a minute than a worried summary can.
Heatwaves and cold snaps deserve their own entries. When the room itself swings, write down the room temperature beside the enclosure readings: a basking spot that suddenly overshoots on a hot afternoon is a room problem, not a lamp problem, and the fix is different.
Keeping those dated readings in KinsLe's Pet Passport puts the climate log beside the chameleon's feeding, shedding, and vet history, so the full picture of its care is in one place.