On average, the coolest month in St, John's County, Florida is January. During this time, daytime temperatures average 68 degrees Fahrenheit, while nighttime lows dip to around 44 degrees according to the Weather Channel. The warmest month is normally July, when daytime highs average 92 degrees and nighttime lows average 70 degrees. Late winter and early spring temperatures are typically in the 70s during the day and 50s at night. March and April usually see daytime highs in the 80s and nighttime lows in the 60s. This same temperature pattern is typical for the months of September and October as well.
Precipitation is normally in the form of rain, as temperatures rarely reach below freezing. The least amount of rainfall typically falls in December, with only 2.65 inches of rain being average. The highest amount of precipitation typically comes in September, with 7.4 inches being average according to the Weather Channel. There are usually more than six inches of rain in June and August, with July weighing in at approximately 5.56 inches on average. November, February and April normally see less than 3.0 inches of precipitation. Average January rainfall is 3.39 inches, with March having slightly less than four inches most years
The ultraviolet index in St. John's County, Florida is normally higher than that of the national average. In 2009, the last year that data is available, the average UV index in this county was 6.88 compared to a national average of 5.14. During June, July and August, the monthly average is typically more than 10 but could be as low as 2.05. The UV index is usually the lowest in November and December. During these months, some days are barely measurable, with the index reaching only 0.5. The average UV index for the month of December is typically 2.39.
St. John's County is found on the Eastern coast of Florida in the northern portion of the state. As such, it is susceptible to hurricanes. The St. John's County Emergency Management office suggests evacuation routes for its citizens in the event of a hurricane. These generally involve driving north on highway A1A, then taking a state highway west until reaching Interstate 95. There are also a number of hurricane shelters throughout the county, however Emergency Management personnel recommend using these only if residents are unable to evacuate. In addition to maintaining evacuation routes and shelters, this office also gives advice on how to prepare for this disaster to include a list of recommend supplies to keep on hand.
