At what temperature should I bring my plants inside?

Our cold advisory starts when the night's low reaches 10 °C, and escalates at 0 °C. That first figure matches what most guidance says, and it was arrived at separately: the threshold was raised from 4 °C during a horticultural review because tropical foliage starts suffering nearer 10 to 12 °C.

Do the other weather alerts matter once a plant is indoors?

Only two of the five do. Heavy rain, high wind and heavy snow are suppressed for a plant marked as indoors, because a wall handles them. Heat and cold keep running, since neither is stopped by being on the other side of the glass.

Does an advisory mean the worst night of the week?

Its level does: severity is graded on the harshest night in the run, so an advisory means no night in this forecast reaches the warning line, and a warning means at least one does. Its date does not: the alert sits on the first night that crosses the threshold, which can be days before the night it is graded on.

Should I stop feeding when I bring plants in?

While a heat or cold alert is running, feeding is suppressed regardless of the season. After that it depends on the light and the warmth where you have put the plant rather than on the month, which is the whole subject of the feeding page.

What about repotting before I bring it in?

Not during an alert. The repot hint is held back while a heat or cold alert is active on an outdoor plant, and outside the spring window it is down anyway.

When to Bring Plants Inside

The number you will be given is about 50 °F, which is 10 °C, and it is a reasonable one. We read nineteen sources and copied down every temperature they attach to bringing plants in. Thirteen name a trigger, and between them they publish 40, 45, 50, 55 and 60 °F.

Fifty is the one most repeated, but only ten of the eighteen figures say whether they mean a night-time low — and a night low is not an afternoon reading.

Source	The temperature it gives	Does it say night?
deckers-nursery.com	50 °F	Stated as a night-time low
gardendesign.com	50 °F	Stated as a night-time low
gardendesign.com	50 to 55 °F	Stated as a night-time low
gardeningknowhow.com	45 F	Stated as a night-time low
gardeningknowhow.com	50 F	Stated as a night-time low
hyanniscountrygarden.com	50 °F	Stated as a night-time low
thesill.com	55 °F	Stated as a night-time low
tomsguide.com	below 55 to 60 °F	Stated as a night-time low
yardandgarden.extension.iastate.edu	50s °F	Stated as a night-time low
yardandgarden.extension.iastate.edu	around 50 °F	Stated as a night-time low
fieldreport.caes.uga.edu	50 °F	Does not say if it is a night low
gardeningknowhow.com	below 50 F	Does not say if it is a night low
gardeningknowhow.com	45-50 F	Does not say if it is a night low
hgic.clemson.edu	50 °F	Does not say if it is a night low
homesandgardens.com	45 °F	Does not say if it is a night low
parkviewnursery.com	40 °F	Does not say if it is a night low
wardsnursery.com	45 °F	Does not say if it is a night low
wayne.ces.ncsu.edu	below 50 °F	Does not say if it is a night low

Every bring-in temperature we could find, copied as written. 18 figures transcribed from 13 sources, read end to end on 29 August 2026. Units are copied exactly as each source writes them; nothing here is converted, and nothing here is our own measurement. All of them, from every page, are one free download.

Worked example: Swiss cheese plant (Monstera) out on a covered balcony in early autumn, air 12 °C and 70% humidity, medium airflow. Your spot will score differently. Run it for your own spot →

Cold is one of five

An open window with autumn foliage outside, three small potted plants on the sill and an outdoor thermometer hanging beyond the glass — The window is still open and the tree outside has turned. The thermometer beyond the glass is the number this page is about.

Cold is the event people are warned about. It is not the only one that reaches a plant standing outside; there are five, each with an advisory level and a more serious one:

Event	Raised as an advisory when	Raised as a warning at	Runs for a plant indoors?
Heat	Day's highest reaches 35 °C	40 °C	Yes
Cold	Night's lowest drops to 10 °C	0 °C	Yes
Heavy rain	10 mm in three hours, or 25 mm across the day	50 mm across the day	No
High wind	Gusts reach 10.8 m/s, force 6 on the Beaufort scale	17.2 m/s, force 8	No
Heavy snow	3 mm of water equivalent in three hours, or 10 mm across the day	25 mm across the day	No

The thresholds are read from the alert engine; the last column is the engine's own answer, checked by running each event twice, once as an indoor plant and once as an outdoor one. Only heat and cold survive indoors, because a wall stops rain, wind and snow but does very little to a cold snap at the glass.

Carrying a plant back out switches rain, wind and snow on again, and the light it walks into is the bigger change.

The alert lands on the first night, graded by the worst one

Each event is raised once per forecast run: it sits on the earliest day that crosses the threshold, and it takes its level from the harshest day that does. One declared five-day forecast, run twice, once as a balcony plant and once as the same plant indoors:

Forecast day	High / low	On the balcony	Inside the room
Day 1	18 °C / 14 °C	No alert	No alert
Day 2	16 °C / 8 °C	cold (warning)	cold (warning)
Day 3	15 °C / 9 °C	No alert	No alert
Day 4	12 °C / -1 °C	high wind (advisory)	No alert
Day 5	11 °C / 2 °C	No alert	No alert

One five-day forecast, declared in full and run through the alert engine twice. Two things to notice: the cold alert lands on Day 2, the first day the night low crosses the line rather than the coldest one, though its warning level is graded on that coldest night; and each kind of event is raised once for the run, not once per day.

Day 4 has a night at −1 °C, which is a frost, while the 8 °C night on Day 2 would only rate an advisory on its own. What you get is a single cold warning sitting on Day 2: the date comes from the night that crossed the line first, the level from the frost two nights later. Read the date as "act by then" and the level as "this is how cold the run gets". A plant arriving from a shop rather than from the garden meets the same set of checks, and three of the four can answer on its first day.

What an alert changes besides the plant's address

A row of potted plants along a balcony parapet under a deep roof overhang, the flat’s windows behind them — Sheltered outdoors is still outdoors. The forecast these pots are living in is the real one, not a room equivalent.

An active heat or cold alert does more than suggest moving the pot: the repot hint and the feeding schedule both stand down while it runs. Watering carries on unchanged, because a heatwave already arrives inside the evaporation figures it reads, and because repotting and feeding are both requests for the plant to spend something at the moment it has nothing spare.

Bringing it in is a spot decision too

A plant that has spent the summer outdoors is about to lose most of its light in one afternoon. The place you put it decides whether it merely sulks or drops half its leaves, and the two spots people reach for first, the empty corner and the shelf away from the window, are usually the worst two in the room.

Read the place you plan to put it before you carry it in, with the free spot checker. Cold at the glass is worth checking too, since the comfortable minimum varies by six degrees across ordinary houseplants, and a leaf touching a winter window is colder than the room it is in.

Thresholds come out of the alert engine rather than from a forecast service, and the wind levels are the Beaufort scale, force 6 and force 8. The indoor and outdoor columns come from running each event twice.

By GrowSpot · Published August 15, 2026 · Last updated August 30, 2026

Plant photo credits