Meeker
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Meeker clear sky chart from 2005-11-06 to 2024-11-30.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	4 8% 3 6% 4 4 4 4 6% 7% 49%	105449
	Night	5% 9% 3 6% 4 4 4 3 5% 7% 49%	102869
Transparency	Day	33% 5% 8% 21% 20% 11%	105204
	Night	34% 5% 10% 23% 20% 9%	102704
Seeing	Day	11% 16% 29% 27% 14% 3	15564
	Night	10% 9% 24% 35% 19% 3	25711

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	4 16% 7% 12% 6% 5% 4 4 5% 6% 32%	2606
	11th to 20th	Day	5% 17% 7% 15% 5% 3 5% 3 4 5% 30%	2860
	21st to end	Day	3 18% 6% 9% 4 3 4 2 4 5% 41%	3146
February	1st to 10th	Day	5% 17% 5% 9% 5% 5% 5% 3 5% 6% 36%	1710
	11th to 20th	Day	6% 19% 5% 9% 4 4 3 2 4 7% 36%	1665
	21st to end	Day	4 15% 6% 9% 5% 6% 4 4 5% 5% 37%	1564
March	1st to 10th	Day	3 16% 7% 10% 5% 4 4 2 5% 5% 38%	3412
	11th to 20th	Day	3 10% 3 7% 5% 5% 6% 5% 6% 6% 44%	3490
	21st to end	Day	4 18% 6% 9% 7% 5% 5% 4 6% 7% 28%	3845
April	1st to 10th	Day	6% 13% 3 7% 5% 4 4 4 6% 6% 42%	2280
	11th to 20th	Day	7% 13% 3 7% 6% 4 5% 5% 5% 6% 39%	2251
	21st to end	Day	6% 10% 3 8% 5% 4 5% 4 6% 6% 42%	2312
May	1st to 10th	Day	7% 13% 3 8% 6% 6% 6% 5% 6% 7% 33%	4110
	11th to 20th	Day	4 4 2 6% 4 5% 5% 5% 8% 9% 48%	4260
	21st to end	Day	5% 6% 2 7% 4 5% 5% 4 6% 7% 50%	4825
June	1st to 10th	Day	4 4 2 3 3 4 4 4 7% 8% 55%	2660
	11th to 20th	Day	3 3 1 4 3 4 4 4 5% 7% 63%	2660
	21st to end	Day	2 2 1 3 3 4 3 4 6% 6% 66%	2660
July	1st to 10th	Day	2 2 1 3 3 3 3 3 5% 6% 71%	4430
	11th to 20th	Day	2 3 1 4 4 5% 6% 5% 9% 11% 51%	4286
	21st to end	Day	3 2 1 4 4 5% 5% 4 6% 8% 58%	4454
August	1st to 10th	Day	3 3 1 5% 5% 6% 6% 5% 9% 9% 47%	4092
	11th to 20th	Day	3 3 1 4 4 5% 5% 5% 8% 9% 54%	3997
	21st to end	Day	3 3 1 4 3 4 4 3 6% 8% 60%	4180
September	1st to 10th	Day	5% 2 1 4 3 4 4 3 6% 7% 61%	2280
	11th to 20th	Day	4 3 2 4 4 4 4 3 5% 6% 61%	2261
	21st to end	Day	6% 4 1 4 2 3 3 2 3 6% 66%	2009
October	1st to 10th	Day	4 4 1 3 3 2 2 2 3 5% 71%	3170
	11th to 20th	Day	5% 5% 1 3 4 4 5% 4 6% 9% 55%	3150
	21st to end	Day	6% 7% 2 4 2 3 4 3 5% 5% 59%	3438
November	1st to 10th	Day	6% 8% 2 6% 4 4 4 2 5% 6% 54%	1869
	11th to 20th	Day	7% 11% 2 5% 3 4 3 4 4 5% 52%	1681
	21st to end	Day	4 11% 4 7% 4 3 4 3 5% 6% 50%	1596
December	1st to 10th	Day	7% 14% 5% 10% 5% 4 3 2 4 6% 40%	1520
	11th to 20th	Day	7% 12% 4 9% 5% 4 3 4 5% 7% 42%	1926
	21st to end	Day	4 16% 5% 10% 4 3 4 3 5% 7% 38%	2794
January	1st to 10th	Night	4 14% 7% 12% 5% 4 4 3 5% 5% 37%	4376
	11th to 20th	Night	5% 21% 7% 11% 4 3 4 3 5% 6% 31%	4110
	21st to end	Night	5% 19% 5% 9% 4 3 3 3 4 5% 41%	4521
February	1st to 10th	Night	5% 14% 4 10% 5% 4 5% 3 5% 6% 38%	2470
	11th to 20th	Night	5% 13% 4 9% 6% 4 5% 3 6% 6% 39%	2402
	21st to end	Night	4 14% 4 11% 5% 4 4 3 4 7% 41%	1889
March	1st to 10th	Night	3 14% 4 8% 4 4 5% 4 5% 7% 42%	3448
	11th to 20th	Night	4 12% 3 6% 4 3 3 3 5% 6% 51%	3490
	21st to end	Night	6% 16% 4 10% 6% 6% 5% 4 6% 6% 30%	3807
April	1st to 10th	Night	7% 13% 3 7% 4 4 4 4 4 6% 44%	1900
	11th to 20th	Night	7% 12% 3 6% 4 4 5% 4 6% 6% 42%	1877
	21st to end	Night	8% 10% 3 7% 5% 5% 4 3 6% 6% 43%	1865
May	1st to 10th	Night	8% 11% 2 7% 6% 5% 5% 4 6% 6% 40%	2860
	11th to 20th	Night	5% 6% 2 6% 4 5% 5% 4 7% 8% 48%	2630
	21st to end	Night	7% 5% 2 5% 4 4 3 3 5% 7% 56%	2762
June	1st to 10th	Night	4 3 2 3 3 3 5% 5% 8% 7% 57%	1520
	11th to 20th	Night	4 4 2 4 3 4 3 3 6% 7% 59%	1520
	21st to end	Night	3 2 1 3 2 3 4 4 5% 9% 65%	1520
July	1st to 10th	Night	3 1 1 3 3 3 4 4 5% 8% 66%	2540
	11th to 20th	Night	2 3 1 5% 4 6% 6% 5% 9% 11% 48%	2666
	21st to end	Night	2 2 1 4 4 4 4 4 6% 8% 62%	3109
August	1st to 10th	Night	2 3 1 4 4 5% 5% 6% 7% 9% 54%	2847
	11th to 20th	Night	2 2 1 5% 5% 5% 6% 5% 6% 9% 53%	2842
	21st to end	Night	3 2 1 4 3 3 4 4 7% 10% 59%	3487
September	1st to 10th	Night	4 2 1 3 2 3 4 3 5% 7% 65%	1900
	11th to 20th	Night	4 3 1 4 3 4 3 3 5% 7% 63%	1915
	21st to end	Night	5% 4 1 3 2 2 3 2 4 5% 68%	2171
October	1st to 10th	Night	4 3 1 3 2 2 3 3 4 4 72%	3800
	11th to 20th	Night	4 5% 1 4 2 3 3 3 5% 10% 59%	3778
	21st to end	Night	6% 7% 2 4 3 3 3 2 4 5% 61%	4120
November	1st to 10th	Night	7% 7% 2 5% 4 3 3 3 5% 6% 55%	2408
	11th to 20th	Night	5% 11% 2 5% 3 3 4 3 5% 7% 52%	2715
	21st to end	Night	7% 12% 3 6% 3 3 3 3 4 6% 51%	2800
December	1st to 10th	Night	7% 12% 4 8% 4 3 3 3 4 5% 45%	2660
	11th to 20th	Night	7% 13% 4 9% 5% 4 5% 4 5% 7% 38%	3271
	21st to end	Night	5% 13% 5% 10% 5% 4 4 3 5% 6% 41%	4873

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	53% 5% 10% 21% 10% 1	2607
	11th to 20th	Day	57% 5% 14% 16% 7%	2860
	21st to end	Day	48% 3 15% 22% 9% 2	3146
February	1st to 10th	Day	50% 6% 14% 18% 11% 1	1710
	11th to 20th	Day	51% 4 9% 21% 13% 2	1674
	21st to end	Day	47% 6% 9% 20% 15% 2	1564
March	1st to 10th	Day	48% 4 7% 25% 15% 1	3412
	11th to 20th	Day	41% 5% 10% 33% 10% 2	3490
	21st to end	Day	53% 7% 7% 22% 8% 2	3845
April	1st to 10th	Day	40% 6% 10% 19% 19% 5%	2280
	11th to 20th	Day	44% 6% 8% 21% 18% 3	2254
	21st to end	Day	40% 7% 7% 26% 19% 1	2312
May	1st to 10th	Day	46% 8% 5% 19% 19% 3	4110
	11th to 20th	Day	29% 8% 6% 31% 23% 3	4264
	21st to end	Day	31% 6% 5% 23% 30% 4	4825
June	1st to 10th	Day	24% 5% 8% 23% 27% 13%	2660
	11th to 20th	Day	21% 5% 6% 14% 30% 24%	2660
	21st to end	Day	17% 4 4 15% 32% 28%	2660
July	1st to 10th	Day	15% 4 5% 9% 19% 47%	4361
	11th to 20th	Day	21% 7% 8% 16% 23% 24%	4211
	21st to end	Day	22% 5% 8% 15% 18% 33%	4314
August	1st to 10th	Day	29% 7% 12% 19% 15% 17%	4078
	11th to 20th	Day	24% 7% 11% 19% 25% 15%	4036
	21st to end	Day	22% 5% 9% 20% 24% 20%	4179
September	1st to 10th	Day	21% 6% 6% 15% 27% 25%	2280
	11th to 20th	Day	25% 4 7% 19% 29% 16%	2261
	21st to end	Day	21% 3 4 24% 37% 11%	2009
October	1st to 10th	Day	19% 3 5% 16% 34% 23%	3170
	11th to 20th	Day	24% 6% 9% 31% 27% 3	3150
	21st to end	Day	27% 5% 9% 36% 21% 3	3438
November	1st to 10th	Day	33% 3 11% 26% 25% 3	1869
	11th to 20th	Day	35% 3 13% 27% 21% 2	1681
	21st to end	Day	36% 4 12% 28% 17% 3	1596
December	1st to 10th	Day	47% 4 15% 22% 9% 3	1520
	11th to 20th	Day	42% 4 12% 27% 14% 1	1924
	21st to end	Day	47% 4 10% 16% 20% 2	2794
January	1st to 10th	Night	50% 4 12% 22% 11% 1	4376
	11th to 20th	Night	54% 5% 13% 18% 8% 1	4110
	21st to end	Night	48% 3 17% 21% 9% 3	4521
February	1st to 10th	Night	49% 5% 12% 22% 12% 1	2470
	11th to 20th	Night	46% 5% 8% 24% 14% 2	2403
	21st to end	Night	43% 5% 10% 22% 16% 3	1889
March	1st to 10th	Night	41% 5% 7% 29% 18% 1	3448
	11th to 20th	Night	34% 3 12% 32% 16% 3	3490
	21st to end	Night	53% 4 10% 23% 9% 1	3807
April	1st to 10th	Night	41% 5% 10% 21% 18% 6%	1900
	11th to 20th	Night	39% 6% 10% 24% 17% 4	1877
	21st to end	Night	42% 3 8% 25% 20% 2	1865
May	1st to 10th	Night	42% 7% 7% 19% 23% 3	2860
	11th to 20th	Night	32% 5% 9% 32% 20% 3	2631
	21st to end	Night	29% 4 6% 26% 31% 5%	2762
June	1st to 10th	Night	22% 4 11% 25% 25% 14%	1520
	11th to 20th	Night	24% 4 8% 14% 23% 27%	1520
	21st to end	Night	17% 3 5% 16% 29% 30%	1520
July	1st to 10th	Night	17% 5% 7% 10% 21% 40%	2500
	11th to 20th	Night	23% 7% 9% 21% 21% 18%	2618
	21st to end	Night	19% 5% 10% 16% 24% 25%	3011
August	1st to 10th	Night	24% 7% 12% 22% 15% 20%	2838
	11th to 20th	Night	27% 7% 14% 16% 21% 16%	2869
	21st to end	Night	20% 6% 10% 18% 22% 24%	3487
September	1st to 10th	Night	19% 5% 7% 17% 24% 28%	1900
	11th to 20th	Night	21% 4 10% 22% 25% 19%	1915
	21st to end	Night	20% 3 5% 20% 39% 13%	2171
October	1st to 10th	Night	17% 3 5% 15% 37% 23%	3800
	11th to 20th	Night	21% 6% 10% 31% 28% 5%	3778
	21st to end	Night	26% 4 8% 34% 24% 3	4120
November	1st to 10th	Night	31% 4 9% 27% 25% 4	2408
	11th to 20th	Night	32% 5% 11% 29% 19% 3	2715
	21st to end	Night	37% 3 8% 29% 20% 4	2800
December	1st to 10th	Night	43% 4 15% 21% 15% 2	2660
	11th to 20th	Night	45% 4 11% 24% 15% 1	3272
	21st to end	Night	46% 4 11% 17% 21% 2	4873

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	23% 13% 25% 25% 13% 2	270
	11th to 20th	Day	16% 18% 34% 26% 6% 1	270
	21st to end	Day	14% 13% 35% 30% 7% 1	297
February	1st to 10th	Day	17% 28% 35% 16% 3 1	270
	11th to 20th	Day	19% 25% 30% 23% 3 1	270
	21st to end	Day	20% 25% 35% 13% 6%	225
March	1st to 10th	Day	20% 30% 28% 17% 5%	439
	11th to 20th	Day	11% 28% 34% 20% 6%	460
	21st to end	Day	19% 29% 34% 14% 3	506
April	1st to 10th	Day	18% 26% 30% 18% 6% 2	460
	11th to 20th	Day	19% 29% 31% 16% 4	452
	21st to end	Day	16% 24% 33% 18% 8% 1	460
May	1st to 10th	Day	16% 24% 32% 19% 8%	463
	11th to 20th	Day	11% 17% 28% 27% 16% 2	599
	21st to end	Day	9% 17% 29% 27% 15% 3	734
June	1st to 10th	Day	5% 14% 25% 32% 18% 5%	680
	11th to 20th	Day	7% 15% 34% 28% 14% 3	680
	21st to end	Day	3 11% 29% 34% 18% 4	680
July	1st to 10th	Day	4 5% 25% 35% 25% 6%	671
	11th to 20th	Day	3 6% 22% 38% 24% 6%	589
	21st to end	Day	4 5% 23% 38% 23% 6%	531
August	1st to 10th	Day	5% 7% 26% 38% 19% 5%	487
	11th to 20th	Day	5% 5% 28% 36% 20% 6%	477
	21st to end	Day	4 7% 30% 35% 19% 4	539
September	1st to 10th	Day	5% 8% 27% 34% 19% 6%	490
	11th to 20th	Day	5% 12% 37% 26% 14% 4	490
	21st to end	Day	9% 18% 21% 30% 18% 5%	409
October	1st to 10th	Day	13% 13% 20% 26% 23% 5%	300
	11th to 20th	Day	10% 15% 27% 27% 20% 1	300
	21st to end	Day	13% 22% 30% 23% 11% 1	330
November	1st to 10th	Day	19% 19% 30% 21% 10% 1	300
	11th to 20th	Day	11% 20% 35% 21% 11% 3	300
	21st to end	Day	14% 17% 29% 28% 10% 1	299
December	1st to 10th	Day	19% 18% 30% 23% 9% 2	270
	11th to 20th	Day	15% 18% 38% 22% 7%	270
	21st to end	Day	20% 20% 33% 22% 5% 1	297
January	1st to 10th	Night	15% 11% 24% 36% 13% 2	922
	11th to 20th	Night	14% 12% 26% 34% 12% 2	760
	21st to end	Night	13% 8% 29% 38% 10% 2	836
February	1st to 10th	Night	13% 11% 32% 33% 9% 1	760
	11th to 20th	Night	11% 14% 30% 35% 10%	744
	21st to end	Night	13% 15% 34% 32% 6%	628
March	1st to 10th	Night	12% 14% 29% 32% 11% 1	760
	11th to 20th	Night	8% 9% 28% 38% 16% 1	760
	21st to end	Night	13% 13% 29% 34% 10% 1	827
April	1st to 10th	Night	13% 16% 28% 35% 8%	570
	11th to 20th	Night	14% 13% 28% 33% 9% 2	563
	21st to end	Night	13% 13% 24% 32% 15% 3	570
May	1st to 10th	Night	12% 12% 28% 32% 15% 1	570
	11th to 20th	Night	9% 7% 21% 36% 23% 4	561
	21st to end	Night	11% 11% 20% 35% 21% 3	617
June	1st to 10th	Night	5% 9% 17% 37% 29% 3	570
	11th to 20th	Night	7% 10% 24% 40% 17% 2	570
	21st to end	Night	4 4 18% 40% 32% 2	570
July	1st to 10th	Night	4 3 14% 36% 39% 5%	555
	11th to 20th	Night	2 2 11% 41% 37% 7%	552
	21st to end	Night	3 1 9% 37% 45% 4	624
August	1st to 10th	Night	5% 2 9% 41% 39% 4	567
	11th to 20th	Night	3 2 11% 44% 36% 3	564
	21st to end	Night	4 2 14% 39% 34% 7%	627
September	1st to 10th	Night	5% 3 13% 39% 36% 4	570
	11th to 20th	Night	5% 4 17% 42% 26% 5%	585
	21st to end	Night	6% 7% 19% 33% 27% 8%	760
October	1st to 10th	Night	9% 6% 21% 38% 21% 4	760
	11th to 20th	Night	9% 6% 23% 39% 20% 3	760
	21st to end	Night	12% 9% 24% 34% 18% 3	836
November	1st to 10th	Night	11% 12% 26% 31% 18% 2	848
	11th to 20th	Night	12% 12% 32% 31% 13% 2	1000
	21st to end	Night	14% 11% 25% 37% 13% 1	1000
December	1st to 10th	Night	15% 10% 29% 34% 11% 1	950
	11th to 20th	Night	18% 11% 28% 31% 11% 1	950
	21st to end	Night	18% 12% 33% 30% 6% 1	1045

Page generated at 2024-11-27 15:30:55. Version ac07

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