Historical weather data, all-time temperature records, and monthly climate averages for Arnold, MO. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Arnold runs mild on average, with a high of 64° and a low of 39° across 56 years of data. The date has a wild range, though — temperatures have swung from a 20° freeze in 1980 to an 87° scorcher in 2011. There's a 36% chance of rain today, so keep an umbrella handy.
Arnold's weather has serious extremes on both ends — the all-time high of 110° in July 1980 and the all-time low of -27° in January 1977 represent a jaw-dropping 137-degree spread. The wettest single day on record dumped 6.2 inches of rain on September 8, 2018, while a February 1966 storm buried the area under 9 inches of snow.
Arnold's summer peaks in mid-July with average highs around 90°, while January is the coldest stretch with highs only reaching 40°. Late April is the wettest stretch of the year, averaging 1.28 inches of precipitation in a single week, so spring travelers should plan accordingly. If you're chasing the sweet spot, May and September offer pleasant highs in the upper 70s to low 80s with less rainfall.