Winters in Keizer are chilly, with temperatures often below freezing, especially in January and December. Spring is a gradual warming period, with March and April seeing significant increases in temperature, but still experiencing some cooler days. Summers are mild, with July and August being the warmest months, but temperatures rarely exceed 37°C (99°F). Autumn brings a return to cooler temperatures, similar to winter, with September and October experiencing a mix of mild and cool days.