Historical weather data, all-time temperature records, and monthly climate averages for Hillsborough, NJ. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Hillsborough sits right in the heart of spring uncertainty — historically, highs range from a bitter 25° to a t-shirt-worthy 77°, which happened just this year. Expect something in between, with the average landing at 59°/37° and a coin-flip 55% chance of rain.
Hillsborough earns its New Jersey stripes with some serious weather extremes — from a scorching 102° in July 1999 to a brutal -3° in February 2015, a 105-degree spread across its history. A single September day in 1999 dropped over 9 inches of rain, and a February 1978 storm buried the area under 15 inches of snow.
Summer is the main event here, with highs peaking around 87° in late July and the wettest stretch of the year arriving right on summer's heels. Winters are genuinely cold — January and February hover in the upper 30s to low 40s — so plan accordingly. Spring and fall offer the most comfortable windows, with May and September both clearing 70°.