How to read the NWS climate report

The final report: Central Park, Oct 17, 2026

1CDUS41 KOKX 1806172CLINYC CLIMATE REPORTNATIONAL WEATHER SERVICE NEW YORK, NY3217 AM EDT SUN OCT 18 2026 .................................... 4...THE CENTRAL PARK NY CLIMATE SUMMARY FOR OCTOBER 17 2026... 5CLIMATE NORMAL PERIOD 1991 TO 2020CLIMATE RECORD PERIOD 1869 TO 2026  6WEATHER ITEM   OBSERVED TIME   RECORD YEAR NORMAL DEPARTURE LAST                VALUE   (LST)  VALUE       VALUE  FROM      YEAR                                                  NORMAL...................................................................TEMPERATURE (F)7 YESTERDAY8  MAXIMUM         62   1208 AM  90    1938  64     -2       639  MINIMUM         43   1159 PM  33    1886  51     -8       47  AVERAGE         53                        58     -5       55   (precipitation, snow, degree days, wind, sky cover, humidity...) 10THE CENTRAL PARK NY CLIMATE NORMALS FOR TODAY                         NORMAL    RECORD    YEAR MAXIMUM TEMPERATURE (F)   64        82      1928 11-  INDICATES NEGATIVE NUMBERS.R  INDICATES RECORD WAS SET OR TIED.MM INDICATES DATA IS MISSING.T  INDICATES TRACE AMOUNT.

1. 1

   The WMO heading. CDUS41 is the product's international heading, KOKX the office that issued it (the NWS in New York), and 180617 the day of the month and the UTC time: the 18th at 06:17 UTC.

2. 2

   The report's code. CLINYC: CLI plus the station's three-letter id. This is the code Kalshi's rules name: "the maximum temperature recorded at New York City (CLINYC)".

3. 3

   When it was issued. 2:17 AM daylight time on Oct 18, after the climate day had ended at midnight standard time (1 AM on the clock). The NWS issues this report between 12:30 and 5:00 AM local time.

4. 4

   The day it covers. October 17, 2026. There is no "VALID TODAY AS OF" line under it, so this is the final report: the first non-preliminary report, the kind Kalshi's contract terms use.

5. 5

   Normals and records. "Normal" is the 1991 to 2020 average for the date; records at Central Park go back to 1869.

6. 6

   The columns. Observed value, the time it happened, the record for the date and its year, the normal, the departure from normal, and last year's value. The time column is local standard time all year, even in summer.

7. 7

   YESTERDAY. The whole day just ended. A preliminary report says TODAY instead.

8. 8

   The line that settles the market. The high was 62°F, at 12:08 AM local standard time: 1:08 AM on the clock, the first minutes of the climate day. The record for Oct 17 is 90°F (1938), the normal 64°F, so the day was 2 below normal; a year earlier it was 63°F. The market compared 62 with its brackets.

9. 9

   The low came at the very end. 43°F at 11:59 PM standard time. The afternoon report (below) had said 50: the low, like the high, can move after it.

10. 10

    Normals for the new day. The normal and record high for Oct 18, the day the report was issued: 64°F and 82°F (1928).

11. 11

    The marks. A minus sign is a negative number, R a record set or tied, MM a missing value (a missing time of the high prints MM too), T a trace of rain or snow.

Source: The report as issued (202610180617-KOKX-CDUS41-CLINYC), via IEM; NWS Instruction 10-1004, section 4.1 (the climate report's format and timing)

The same day's preliminary report

CDUS41 KOKX 172033CLINYC1433 PM EDT SAT OCT 17 2026...THE CENTRAL PARK NY CLIMATE SUMMARY FOR OCTOBER 17 2026...2VALID TODAY AS OF 0400 PM LOCAL TIME.TEMPERATURE (F)3 TODAY4  MAXIMUM         62   1208 AM  90    1938  64     -2       63  MINIMUM         50    249 PM  33    1886  51     -1       47

1. 1

   Issued at 4:33 PM daylight time on the same day, the NWS's mandatory late-afternoon report.

2. 2

   The mark of a preliminary report: the numbers so far, as of 4 PM local time. It doesn't settle anything.

3. 3

   TODAY: the day isn't over.

4. 4

   Here the high held: 62°F at 12:08 AM in both reports. The low didn't: 50 by 4 PM, 43 by midnight.

Source: The report as issued (202610172033-KOKX-CDUS41-CLINYC), via IEM; Kalshi contract terms ("the first official non-preliminary report")

How often the afternoon high holds

Across all 24 stations from May 1, 2026 to Oct 30, 2026, the afternoon report's high matched the final report's on 3896 of 4354 station-days (89%). The final came in higher on 455 (10%); on 430 of those the final report put the high after the afternoon report's cutoff. It came in lower on 3. On 4 station-days the NWS sent a second final report with a different high; Kalshi's terms use the first.

The afternoon report is each day's last preliminary report valid as of 3:00 to 5:59 PM local time; the final is the first report for the whole day. Some offices also issue a morning or an evening report, which are left out here.

Source: Every NWS climate report issued for the 24 stations, via IEM's text archive (Central Park's shown)

Where to read it

• The NWS's own page shows the latest report for a station and lets you step back through recent ones.
• The Iowa Environmental Mesonet's archive keeps every issuance, preliminary and final, for every station.
• The Weather Company's settlement page is the source the rules name since the Aug 14, 2026 events.
• Each city's rules page on Almanac links its station's report, and says how often its afternoon report held.

Source: NWS Chicago: weather observations FAQ (the climate day)

Questions

Every rule, in ten facts · Can these markets be gamed? · Glossary