Climate averages 1991–2020

Oceanside weather
in January.

A mild, moderately wet month: the joint 10th warmest and the 11th driest of the year.

Long-term climate patterns, not a forecast for a particular trip.

Average high 16.9°C Daytime mean, January

Average low 8.3°C Night-time mean, January

Rainfall 62 mm 5 days with ≥1 mm

Daylight 10 h Sunrise to sunset, per day

January is a mild month in Oceanside: daytime highs average 16.9°C and nights cool to about 8.3°C. By daytime temperature it is the joint 10th warmest of the 12 months.

Expect about 62 mm of rain on roughly 5 days, which makes January a moderately wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 10 h 13 min on an average January day.

The nearest other city in this atlas is Vista (13 km away). In January its highs average 17.8°C, 0.9°C warmer than Oceanside, with 73 mm of rain.

Among the 498 cities listed in the United States, Oceanside ranks joint 101st of 498 for the warmest January highs and joint 175th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Oceanside is 7.5°C warmer than that mean.

From January to February, average highs fall by 0.2°C to 16.7°C, and monthly rainfall rises from 62 mm to 74 mm.

The annual picture

January in context

30-year average

Average highAverage low°C

Monthly rainfall

Average total · mm

Averages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated

Every month, side by side

Oceanside climate table

1991–2020

Monthly climate averages for Oceanside, 1991–2020
Month	Average highHigh / low	Average low	Rainfall mm/month	Rain days ≥1 mm/day	Daylight hours/dayDaylight h/day
January, selected	16.9°C8.3°C	8.3°C	62	5.3	10.210 h
February	16.7°C9.0°C	9.0°C	74	6.1	11.011 h
March	17.4°C10.3°C	10.3°C	40	5.3	12.012 h
April	18.6°C11.8°C	11.8°C	17	3.0	13.013 h
May	19.9°C13.7°C	13.7°C	7.5	1.8	13.914 h
June	22.1°C15.7°C	15.7°C	1.7	0.4	14.314 h
July	24.7°C18.1°C	18.1°C	1.2	0.3	14.114 h
August	25.8°C19.1°C	19.1°C	0.6	0.2	13.413 h
September	25.3°C18.4°C	18.4°C	3.3	0.6	12.412 h
October	22.9°C15.6°C	15.6°C	13	2.0	11.411 h
November	19.9°C11.8°C	11.8°C	21	2.7	10.510 h
December	16.9°C8.6°C	8.6°C	46	4.7	10.010 h

Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.

Compare places

January in nearby cities

Distance from Oceanside

Read the numbers correctly

Climate, not a promise.

These patterns help compare months. They cannot tell you the weather on a specific day of your trip.

Sources, method and limits

How these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Oceanside) is explained once on the Oceanside year overview and on the Sources, method and limits page.