- Latitude: 34.1
- Longitude: -117.25
High Temperatures
On May 15 in this location the average high temperature is 79.5 °F (26.4 °C). The lowest recored high temperature was 54.0 °F (12.2 °C) in 1949 and the highest recored high temperature was 102.9 °F (39.4 °C) in 2014. The high temperature is usually* between 73.0 °F (22.8 °C) and 86.0 °F (30.0 °C). About a quarter of the time, the high temperature is less than 73.0 °F (22.8 °C), and another quarter of the time, the high temperature is greater than and 86.0 °F (30.0 °C). About 95% of the time, the high temperature has been between 60.6 °F (15.9 °C) and 98.3 °F (36.8 °C).
Low Temperatures
On May 15 in this location the average low temperature is 53.0 °F (11.7 °C). The lowest recored low temperature was 37.9 °F (3.3 °C) in 1968 and the lowest recored low temperature was 75.2 °F (24.0 °C) in 1997. The low temperature is usually* between 50.2 °F (10.1 °C) and 55.9 °F (13.3 °C). About a quarter of the time, the low temperature is less than 50.2 °F (10.1 °C), and another quarter of the time, the low temperature is greater than and 55.9 °F (13.3 °C). About 95% of the time, the low temperature has been between 44.8 °F (7.1 °C) and 61.3 °F (16.3 °C).
Frost
On May 15 in this location expect the temperatures to drop below freezing for a risk of frost about 0.0% of the time.
Data Source(s)
The data used to compute the average high/low temperatures for this location were taken from the following stations:
- MARCH AIR RESERVE BASE — Integrated Surface Dataset (ISD) station ID: 722860 — Weather Bureau Army Navy (WBAN): 23119 — from year 1933 to 2025
- NORTON AAF — Weather Bureau Army Navy (WBAN): 23122 — from year 2015 to 2025
- ONTARIO INTERNATIONAL ARPT — Integrated Surface Dataset (ISD) station ID: 747040 — Weather Bureau Army Navy (WBAN): 03102 — from year 2005 to 2025
- RIVERSIDE MUNICIPAL ARPT — Integrated Surface Dataset (ISD) station ID: 722869 — Weather Bureau Army Navy (WBAN): 03171 — from year 2006 to 2025
- SAN BERNARDINO INTL — Integrated Surface Dataset (ISD) station ID: 722866 — from year 2009 to 2025
- RIVERSIDE MUNI — Integrated Surface Dataset (ISD) station ID: 722869 — from year 1999 to 2005
- RIVERSIDE/MARCH AFB — Integrated Surface Dataset (ISD) station ID: 722860 — from year 2000 to 2004
- ONTARIO INTL ARPT — Integrated Surface Dataset (ISD) station ID: 747040 — from year 2002 to 2004
- BEAUMONT — Integrated Surface Dataset (ISD) station ID: 722867 — from year 2000 to 2001
- ONTARIO — Integrated Surface Dataset (ISD) station ID: 722865 — from year 2000 to 2000
- ONTARIO — Integrated Surface Dataset (ISD) station ID: 722865 — Weather Bureau Army Navy (WBAN): 93180 — from year 1943 to 1999
- BEAUMONT — Integrated Surface Dataset (ISD) station ID: 722867 — Weather Bureau Army Navy (WBAN): 23156 — from year 1973 to 1999
- SAN BERNARDINO INTERNATIONAL — Integrated Surface Dataset (ISD) station ID: 722866 — Weather Bureau Army Navy (WBAN): 23122 — from year 1943 to 1993
- ONTARIO INTERNATIONAL ARPT — Weather Bureau Army Navy (WBAN): 03102 — from year 1968 to 1972
- BEAUMONT 1 E — Weather Bureau Army Navy (WBAN): 23156 — from year 1948 to 1953