First significant rainfall of summer to bring cooler temps to Portland

After nearly a month of dry weather with only a spattering of rain here and there, the first significant system of the summer is arriving on the Oregon coast Monday morning.

PORTLAND, Ore. (KOIN) — After nearly a month of dry weather with only a spattering of rain here and there, the first significant system of the summer is arriving on the Oregon coast Monday morning.

Light rain will push into the Willamette Valley and that will help to keep temperatures cooler across the metro area, along with scattered light rain from time to time. In fact, daytime highs may only top out in the mid-70s locally. That is below normal for what is typically the hottest week of the year in Portland.

Models are indicating anywhere between a tenth of an inch and two-tenths of an inch of rain possible by the time everything wraps up overnight and into Tuesday morning. However, the amount of rainfall coming is not likely to make any major impact on the largest fires in Oregon. But any rainfall and increase in relative humidity levels will help to slow fire growth and that is a good thing.

As soon as the rainfall comes, the rainfall goes. A large ridge of high pressure is set to build in starting on Wednesday and that will lead to another round of potentially excessive heat with temperatures approaching 95-100 degrees again by the end of the week in the Portland metro area.

Stay with the KOIN 6 News weather team all week long for the latest updates on your changing summer forecast.