Definitions

Heat Wave:  At least 3 consecutive days with high temperatures of at least 90 degrees.

Highest Temperatures:  Mid July through mid August across interior locations. 

Heat Index:  An estimate of how hot it feels when air temperature and humidity are combined.

Heat Advisory:  Issued within 24 hours when the heat index is forecast to reach at least 100 degrees for two consecutive hours. NOTE: There is one exception to this policy. For New York City only, a Heat Advisory is issued when the heat index is forecast to reach 95 degrees for two consecutive days or 100 degrees for
any length of time.

Excessive Heat:  Heat Index of at least 105 degrees for at least 3 hours lasting 2 consecutive days or
a Heat Index of at least 115 degrees for any length of time.  Watch is issued 24 to 48 hours of the event. 
Warning is issued within 24 hours of the event.

Short Range Forecasts - National Weather Service - Upton, NY


Excessive Heat Outlooks:  Contained in the Hazardous Weather Outlook (HWO)

     Days 2 to 7 Section, 3 to 5 days before the anticipated event:  

Excessive Heat Watches:  Issued as Non-Precip Watch (NPW) 24 to 48 hours before event.
                                               
Excessive Heat Warnings:  Issued as Non-Precip Warning (NPW) within 24 hours of event.

Heat Advisories:  Issued as Non-Precip Warning (NPW) within 24 hours of event.

3 Hour Heat Index (Apparent Temperature) Forecasts through Day 3 (Next 72 hours)

Hourly Observations (heat index values of at least 90 degrees will appear in remarks section).

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Medium Range Forecasts - Hydrometeorological Prediction Center's Outlooks

Days 3-7 Heat Index Forecasts for New York City

Daily Maximum Heat Index Forecasts:  Chance of Heat Index Reaching 95, 100, and 105.   

Daily Mean Heat Index Forecasts:  Chance of Heat Index Reaching 85, 90, and 95 degrees.

Daily Minimum Heat Index Forecasts:  Chance of Heat Index Reaching 75, 80, and 85 degrees.

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Long Range Forecasts - Climate Prediction Center's National Outlooks

Seasonal Temperature & Precipitation Outlooks for New York City

National Outlooks

Monthly Temperature & Precipitation

8-14 Day Temperature

8-14 Day Precipitation

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Air Quality Forecasts

Climatology

Daily Normal Max T	Daily Record Max T	Heatwaves	90+ Days by Month/Year	100+ Days by Month/Year
CPK	CPK	CPK	CPK	CPK
LGA	LGA	LGA	LGA	LGA
EWR	EWR	EWR	EWR	EWR
JFK	JFK	JFK	JFK	JFK
BDR	BDR	BDR	BDR	BDR
ISP	ISP	ISP	ISP	ISP

Heat Wave Safety Tips

• Slow down. Strenuous activities should be reduced, eliminated, or rescheduled to the coolest time of the day. Individuals at risk should stay in the coolest available place, not necessarily indoors.
• Dress for summer. Lightweight, light-colored clothing reflects heat and sunlight, and helps your body maintain normal temperatures.
• Foods (like proteins) that increase metabolic heat production also increase water loss.
• Drink plenty of water or non-alcoholic fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don't feel thirsty.
• Do not drink alcoholic beverages.
• Spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, spending some time each day (during hot weather) in an air conditioned environment affords some protection.
• Never leave persons, especially children, and pets in a closed, parked vehicle
• Don't get too much sun. Sunburn makes the job of heat dissipation that much more difficult.