Ontario climate

Ontario Weather in May

NOAA 1991-2020 normals for Ontario Ksrv, 2 km from Ontario

Average highs run from 68°F on May 1 to 78°F on May 31, and lows from 42°F to 51°F. Normal precipitation for the month is 1.41 in over about 7 wet days.

May day by day

The normal high and low for each date, and the record, in °F.

Normal daily high and low temperature at Ontario, in °F, with the record for each date.20406080100120151015202530
  • Normal low
  • Normal high
  • Record high
  • Record low

May at a glance

Average high
74°F
Average low
47°F
Precipitation
1.41 in
Record high
100°FMay 28, 2003
Record low
26°FMay 8, 2002
Chance of a freeze
25%
Days of 90°F or more
2.1
Daylight
14 h 12 min to 15 h 15 min
Cloud cover
59%
Humidity
49%
Dew point
38°F
Wind
6.9 mph

Every day of the month

A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.

DateNormal highNormal lowRecord highRecord lowChance wetChance of snow
May 168°F42°F84°F 199827°F 201321%0%
May 269°F42°F85°F 200429°F 200821%0%
May 369°F43°F87°F 202335°F 201121%0%
May 470°F43°F87°F 201730°F 201121%0%
May 570°F43°F86°F 202031°F 199921%0%
May 670°F44°F91°F 202131°F 199921%0%
May 771°F44°F84°F 199828°F 201021%0%
May 871°F44°F86°F 201326°F 200221%0%
May 972°F45°F90°F 201331°F 199921%0%
May 1072°F45°F91°F 201328°F 199922%0%
May 1172°F45°F93°F 201328°F 199922%0%
May 1273°F46°F94°F 201329°F 200022%0%
May 1373°F46°F96°F 201328°F 200922%0%
May 1473°F46°F91°F 200633°F 201722%0%
May 1574°F47°F94°F 200640°F 199822%0%
May 1674°F47°F94°F 200637°F 199922%0%
May 1774°F47°F95°F 200634°F 201122%0%
May 1875°F48°F96°F 200837°F 200322%0%
May 1975°F48°F91°F 202331°F 200322%0%
May 2075°F48°F94°F 202335°F 200322%0%
May 2175°F48°F93°F 202335°F 201022%0%
May 2276°F49°F88°F 200137°F 201022%0%
May 2376°F49°F95°F 200130°F 201022%0%
May 2476°F49°F98°F 200138°F 200222%0%
May 2576°F50°F92°F 202637°F 201022%0%
May 2677°F50°F87°F 200140°F 201122%0%
May 2777°F50°F91°F 200140°F 201122%0%
May 2877°F50°F100°F 200336°F 201122%0%
May 2977°F51°F98°F 202039°F 200422%0%
May 3078°F51°F98°F 202038°F 200621%0%
May 3178°F51°F98°F 202538°F 200021%0%

Chance of rain

The chance of at least 0.01 inch of precipitation on each date at Ontario, in percent, and of at least 0.1 inch of snowfall.05101520251102030
  • Chance of a wet day
  • Chance of snowfall

Sunrise and sunset

Times for 2026, local time (MDT).

May 1
sunrise 6:39 AM, sunset 8:51 PM
May 31
sunrise 6:08 AM, sunset 9:23 PM

Every day of May: sun and moon

Other months

Sources

Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00356294 (Ontario Ksrv), public domain. Records: NOAA GHCN-Daily, station USW00024162, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.