Average Precipitation for Oregon in May

The tables below give monthly averages for rainfall plus snowfall during May at cities, towns and lakes in Oregon.

Each place has a total for the amount of precipitation it usually receives this month. There is also a count of the number of days with wet weather, when precipitation amounts to 0.01 inches (0.25 millimetres) or more.

The precipitation totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.

You can jump to a separate table for each region of the state: Oregon Coast, Willamette Valley, Cascade Mountains, Central Oregon and Eastern Oregon.

Oregon Coast

Average monthly precipitation in May
Days	Place	Inches	Millimetres
16	Astoria	3.4	86
11	Brookings	3.9	99
11	Gold Beach	3.5	88
13	Newport	3.0	75
12	North Bend	3.0	75
11	Port Orford	3.4	86
14	Seaside	3.9	98
15	Tillamook	4.6	116

Willamette Valley

May averages for total rainfall plus snowfall
Days	Place	Inches	Millimetres
13	Corvallis	2.3	59
12	Eugene	2.5	62
14	Portland	2.8	70
12	Salem	2.3	57

Cascade Mountains

Average amount of rain and snow in May
Days	Place	Inches	Millimetres
12	Crater Lake Park	3.7	93
16	Detroit Lake Dam	6.0	153
14	Government Camp	5.8	146
9	Grants Pass	1.4	35
11	Howard Prairie Lake Dam	2.0	52
8	Klamath Falls	1.0	26
9	Lakeview	1.4	35
9	Medford	1.3	34
10	Roseburg	2.1	52
16	Three Lynx	4.4	112
13	Toketee Falls	3.3	83
9	Wickiup Reservoir Dam	1.3	34

Central Oregon

Precipitation totals for May
Days	Place	Inches	Millimetres
5	Bend	1.0	25
9	Hood River	1.3	34
8	Madras	1.1	28
6	The Dalles	0.8	19

Eastern Oregon

Total precipitation during May
Days	Place	Inches	Millimetres
10	Heppner	1.7	43
9	La Grande	2.2	57
9	Lake Owyhee Dam	1.1	29
7	Ontario	1.4	36
10	Pendleton	1.5	37
10	Seneca	1.7	43
11	Summer Lake	1.4	36