These examples are all fine and would be understood by most native speakers.

I disagree with the linked site. Fever can be and is used for both mild and high temperatures.

"You have a little temperature" is OK because in this case temperature is not countable, it's referring to the degree of fever. One can have a little temperature (fever) the same way one can have a little dirt on one's nose. You would not say you have "two fevers" unless you mean two separate occasions where you had a fever.

Another common expression is "running a fever."

Cathy was running a fever so we kept her home from school.

The text you quoted is not really correct about fever versus temperature.

When referring to a fever that is not high, you'll often hear the phrases "slight fever," "mild fever," or "low-grade fever." This is common usage, and not wrong at all.

Usually these mean a body temperature that's above normal, but below the threshold of of serious concern, usually up to 101F or 38C.

The common term for a high fever is usually just high fever and usually means a fever that's high enough to be of serious medical concern, generally above 102 to 103 F (39-40C.)

Medically, a fever is defined as a temperature above 100.4F/38C, but normal body temperature varies per person, and the ranges differ for children versus adults. These are guidelines, not hard rules.

These examples are all fine and would be understood by most native speakers.

"You have a little temperature" is OK because in this case temperature is not countable, it's referring to the degree of fever. One can have a little temperature (fever) the same way one can have a little dirt on one's nose. You would not say you have "two fevers" unless you mean two separate occasions where you had a fever.

Another common expression is "running a fever."

Cathy was running a fever so we kept her home from school.

The text you quoted is not really correct about fever versus temperature and I disagree with the linked site. Fever can be and is used for both mild and high temperatures. It's easy to find examples.

When referring to a fever that is not high, you'll often hear the phrases "slight fever," "mild fever," or "low-grade fever." This is common usage, and not wrong at all.

Usually these mean a body temperature that's above normal, but below the threshold of concern, usually up to 101F or 38C.

The common term for a high fever is usually just high fever and usually means a fever that's high enough to be of serious medical concern, generally above 102 to 103 F (39-40C.)

Medically, a fever is defined as a temperature above 100.4F/38C, but normal body temperature varies per person, and the ranges differ for children versus adults. These are guidelines, not hard rules.

These examples are all fine and would be understood by most native speakers.

I disagree with the linked site. Fever can be and is used for both mild and high temperatures.

"You have a little temperature" is OK because in this case temperature is not countable, it's referring to the degree of fever. One can have a little temperature (fever) the same way one can have a little dirt on one's nose. You would not say you have "two fevers" unless you mean two separate occasions where you had a fever.

The text you quoted is not really correct. Although fever has connotations of being less severe than fever, they are often used interchangeably.

When referring to a fever that is not high, you'll often hear the phrases "slight fever," "mild fever," or "low-grade fever." This is quite common usage, and not wrong at all.

Usually these mean a body temperature that's above normal, but below the threshold of of serious concern, usually up to 101F or 38C. A high fever is usually one above 102 to 103 F (39-40C) though this varies widely per person, and the ranges differ for children versus adults.

The common term for a high fever is mostly just "high fever."

These examples are all fine and would be understood by most native speakers.

I disagree with the linked site. Fever can be and is used for both mild and high temperatures.

"You have a little temperature" is OK because in this case temperature is not countable, it's referring to the degree of fever. One can have a little temperature (fever) the same way one can have a little dirt on one's nose. You would not say you have "two fevers" unless you mean two separate occasions where you had a fever.

Another common expression is "running a fever."

Cathy was running a fever so we kept her home from school.

The text you quoted is not really correct about fever versus temperature.

When referring to a fever that is not high, you'll often hear the phrases "slight fever," "mild fever," or "low-grade fever." This is common usage, and not wrong at all.

Usually these mean a body temperature that's above normal, but below the threshold of of serious concern, usually up to 101F or 38C.

The common term for a high fever is usually just high fever and usually means a fever that's high enough to be of serious medical concern, generally above 102 to 103 F (39-40C.)

Medically, a fever is defined as a temperature above 100.4F/38C, but normal body temperature varies per person, and the ranges differ for children versus adults. These are guidelines, not hard rules.