Moderate, temperate are often used interchangeably to denote not excessive in degree, amount, or intensity.
When contrasted moderate often connotes absence or avoidance of excess and is opposed to excessive and immoderate, while temperate connotes deliberate restraint or restriction and is opposed to intemperate and inordinate; thus, “a moderate drinker” suggests free but far from excessive indulgence in intoxicants, and “a temperate drinker” suggests restrained and cautious indulgence; “moderate enthusiasm” suggests lukewarmness, “temperate enthusiasm” suggests keeping a hold over one’s exhibition of feeling; one’s anger may be far from moderate, yet one’s reply may be temperate.
Especially in technical language moderate and temperate often denote falling or staying within a range midway between extremes or designate a point (as in a scale) characterized neither by excess nor by deficiency of something understood. When so used they are not usually interchangeable, for custom or terminology has determined the selection.
In this sense both moderate and temperate have two antonyms, one on the side of deficiency and the other on the side of excess. These antonyms are usually specific and vary according to the application, for example: light and strong (of breezes); arctic and torrid (of climate); abstemious and gluttonous (of eating); mild and violent (of something having force and intensity).