1. The temperature here is of medium.
2. The temperature here is of average.
3. The temperature here is neither low now high.
(Would you correct errors?)
3. is probably best. But we don't know what the lows and highs are.
1 and 2 are wrong. The word "of" shouldn't be there. Also -- we have no frame of reference to what is "medium" or "average."
We might say: "We have moderate temperatures here."
But without a reference point -- that isn't very clear. To me, moderate temperatures are in the 60s and 70s Fahrenheit. But to many people in the world, those are either cold or hot temperatures.
3. small typing error:
The temperature here is neither low nor high.
Yes, I can help correct the errors in the statements you provided:
1. The temperature here is of medium -> The correct phrase would be "The temperature here is moderate."
2. The temperature here is of average -> The correct phrase would be "The temperature here is normal."
3. The temperature here is neither low now high -> There seems to be a typo. The correct phrase would be "The temperature here is neither low nor high."
These corrected statements reflect a range of temperature without specifying a specific value.