Best time to visit Tri-Cities

Tri-Cities is a city of two halves. September scores 93 and December scores 40 — a 53-point swing, which is the difference between a holiday and an endurance test. The month you pick matters more here than almost anywhere. 5 of the twelve months sit within ten points of the best, so there is more than one right answer.

July is the warmest month at 34.3 °C and December the coolest at 6.7 °C — a 27.6 °C spread across the year. Around 74 days a year top 30 °C, concentrated in July and the months either side. 56 nights a year dip below freezing.

There is a real wet season here. January and December carry the rain — up to 10 wet days in a month — while July to September drop as low as 1. That 9-day gap is the biggest single difference between a good month and a bad one in Tri-Cities, and it moves further than the temperature does.

Daylight runs from 8.6 hours in winter to 15.8 in summer, enough to notice on a sightseeing itinerary.

The three strongest months are September, May, October. The one to think twice about is December. Each month below has its own page with rainfall reliability, extremes, daylight and crowd levels.

Tri-Cities month by month