Global temperature, Sep 1999

Global anomaly+0.39°C1951–1980

Rank among all Seps30 / 146warmest first

N. Hemisphere+0.40°C

S. Hemisphere+0.37°C

vs same month last year−0.03°C

CO₂ (Mauna Loa)364.95 ppm

All months of 1999

Jan+0.48°C

Feb+0.64°C

Mar+0.33°C

Apr+0.32°C

May+0.26°C

Jun+0.36°C

Jul+0.39°C

Aug+0.31°C

Sep ◀+0.39°C

Oct+0.34°C

Nov+0.37°C

Dec+0.40°C

This month+0.39°C

Same month, previous year+0.42°C

Same month 10 years earlier+0.35°C

Same month 50 years earlier−0.14°C

Sep average 1991–2020+0.58°C

Warmest Sep on record (2023)+1.48°C

Year	Global	NH	SH	Rank
1989	+0.35°C	+0.23°C	+0.46°C	33
1990	+0.23°C	+0.42°C	+0.05°C	40
1991	+0.44°C	+0.36°C	+0.52°C	27
1992	−0.01°C	−0.18°C	+0.18°C	68
1993	+0.11°C	−0.06°C	+0.30°C	50
1994	+0.31°C	+0.33°C	+0.30°C	36
1995	+0.33°C	+0.43°C	+0.24°C	35
1996	+0.26°C	+0.04°C	+0.47°C	38
1997	+0.52°C	+0.52°C	+0.55°C	25
1998	+0.42°C	+0.61°C	+0.24°C	28
1999	+0.39°C	+0.40°C	+0.37°C	30
2000	+0.39°C	+0.36°C	+0.41°C	29
2001	+0.52°C	+0.56°C	+0.47°C	24
2002	+0.64°C	+0.62°C	+0.65°C	18
2003	+0.62°C	+0.78°C	+0.47°C	20
2004	+0.50°C	+0.59°C	+0.42°C	26
2005	+0.72°C	+0.89°C	+0.54°C	16
2006	+0.66°C	+0.82°C	+0.50°C	17
2007	+0.60°C	+0.68°C	+0.53°C	22
2008	+0.60°C	+0.56°C	+0.65°C	21
2009	+0.72°C	+0.85°C	+0.59°C	15

Rank 388 of all 1760 months on record. Temperatures are anomalies vs the 1951–1980 average (NASA GISTEMP v4); values can be revised later.