Crex Meadows
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Crex Meadows clear sky chart from 2005-11-06 to 2026-04-17.

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	13% 9% 3 8% 5% 4 4 4 5% 7% 37%	132330
	Night	12% 10% 4 9% 5% 4 4 4 5% 6% 36%	130093
Transparency	Day	45% 5% 13% 24% 11% 1	135856
	Night	47% 5% 12% 22% 12% 1	134642
Seeing	Day	16% 10% 31% 26% 14% 4	17979
	Night	16% 8% 31% 32% 11% 1	28026

By Month

Percentage Cloud Cover SE (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	9% 14% 7% 17% 8% 5% 5% 3 4 4 25%	4691
	11th to 20th	Day	6% 13% 7% 14% 7% 7% 7% 7% 8% 5% 19%	4710
	21st to end	Day	5% 14% 6% 12% 5% 5% 6% 4 6% 7% 30%	5630
February	1st to 10th	Day	9% 13% 4 10% 7% 5% 4 4 5% 7% 32%	1890
	11th to 20th	Day	7% 12% 4 8% 6% 5% 5% 4 5% 7% 36%	1844
	21st to end	Day	10% 11% 4 11% 7% 5% 5% 3 5% 7% 34%	1636
March	1st to 10th	Day	11% 10% 3 7% 4 3 4 3 5% 8% 43%	4815
	11th to 20th	Day	10% 10% 3 8% 5% 4 4 4 5% 8% 38%	5090
	21st to end	Day	21% 11% 4 9% 4 4 4 3 5% 6% 29%	5718
April	1st to 10th	Day	16% 12% 4 9% 5% 4 5% 4 5% 6% 32%	2520
	11th to 20th	Day	19% 13% 3 8% 4 4 4 3 5% 6% 30%	2446
	21st to end	Day	22% 10% 3 8% 5% 5% 5% 3 4 6% 30%	2596
May	1st to 10th	Day	14% 6% 2 6% 4 4 4 3 4 6% 48%	6268
	11th to 20th	Day	17% 8% 3 7% 4 4 4 3 4 5% 41%	6319
	21st to end	Day	16% 8% 3 7% 4 4 5% 4 6% 8% 36%	6935
June	1st to 10th	Day	11% 5% 2 6% 5% 4 4 4 6% 8% 44%	2800
	11th to 20th	Day	14% 7% 3 7% 6% 5% 4 4 6% 8% 37%	2800
	21st to end	Day	12% 5% 2 6% 5% 5% 5% 5% 8% 10% 38%	2996
July	1st to 10th	Day	9% 5% 2 5% 4 4 5% 5% 7% 11% 45%	6458
	11th to 20th	Day	10% 5% 2 4 3 3 3 3 6% 9% 51%	6360
	21st to end	Day	9% 5% 2 5% 3 4 4 4 6% 10% 48%	6924
August	1st to 10th	Day	12% 7% 2 6% 4 4 5% 4 6% 9% 41%	4317
	11th to 20th	Day	13% 5% 2 6% 4 5% 5% 4 6% 9% 42%	4171
	21st to end	Day	13% 7% 2 7% 4 4 4 3 5% 7% 43%	4449
September	1st to 10th	Day	11% 5% 2 6% 4 5% 5% 3 6% 9% 45%	2400
	11th to 20th	Day	12% 5% 2 7% 4 4 4 5% 6% 7% 44%	2400
	21st to end	Day	15% 6% 2 5% 4 3 4 3 6% 8% 44%	2090
October	1st to 10th	Day	17% 8% 2 5% 4 4 4 4 7% 8% 39%	2000
	11th to 20th	Day	18% 11% 3 7% 5% 4 4 3 4 5% 36%	2000
	21st to end	Day	19% 12% 3 6% 5% 5% 4 3 4 6% 33%	2117
November	1st to 10th	Day	13% 13% 4 9% 5% 4 5% 4 5% 6% 33%	1732
	11th to 20th	Day	13% 15% 5% 11% 6% 4 4 4 5% 6% 27%	1680
	21st to end	Day	15% 13% 4 10% 5% 4 5% 3 5% 6% 31%	1680
December	1st to 10th	Day	8% 14% 6% 16% 13% 5% 5% 4 4 5% 20%	2690
	11th to 20th	Day	12% 16% 8% 10% 6% 4 3 3 4 5% 29%	3088
	21st to end	Day	21% 19% 7% 17% 7% 5% 4 2 2 3 13%	4070
January	1st to 10th	Night	9% 13% 6% 15% 8% 5% 4 3 4 5% 28%	8232
	11th to 20th	Night	6% 13% 6% 13% 8% 7% 9% 7% 6% 5% 20%	8280
	21st to end	Night	5% 15% 6% 10% 6% 5% 5% 4 5% 6% 32%	8582
February	1st to 10th	Night	7% 11% 5% 10% 6% 5% 5% 4 5% 6% 35%	2730
	11th to 20th	Night	6% 10% 4 10% 6% 5% 5% 4 5% 6% 37%	2663
	21st to end	Night	11% 12% 3 9% 7% 5% 5% 3 5% 6% 34%	2168
March	1st to 10th	Night	11% 7% 2 7% 4 4 4 3 4 6% 48%	5287
	11th to 20th	Night	10% 10% 3 10% 5% 5% 5% 4 6% 7% 34%	5090
	21st to end	Night	21% 13% 4 10% 4 4 3 2 5% 5% 29%	5452
April	1st to 10th	Night	19% 11% 3 6% 5% 4 3 2 5% 5% 35%	2100
	11th to 20th	Night	21% 10% 3 6% 4 4 4 3 5% 4 36%	2035
	21st to end	Night	20% 10% 3 7% 4 4 4 4 5% 6% 33%	1800
May	1st to 10th	Night	13% 6% 2 6% 4 4 4 2 4 6% 48%	3647
	11th to 20th	Night	14% 7% 2 5% 3 3 3 3 5% 8% 48%	3596
	21st to end	Night	14% 9% 3 6% 4 4 4 4 6% 8% 38%	3942
June	1st to 10th	Night	11% 5% 2 6% 5% 5% 5% 4 6% 10% 42%	1600
	11th to 20th	Night	11% 6% 2 5% 5% 5% 5% 3 7% 7% 43%	1592
	21st to end	Night	9% 6% 2 6% 4 5% 5% 4 6% 7% 46%	1400
July	1st to 10th	Night	8% 3 2 5% 4 4 4 4 7% 9% 50%	3486
	11th to 20th	Night	8% 4 2 5% 4 3 4 3 6% 8% 53%	3617
	21st to end	Night	10% 6% 2 5% 3 4 4 4 6% 7% 49%	3947
August	1st to 10th	Night	10% 6% 2 6% 4 3 3 4 5% 8% 48%	2826
	11th to 20th	Night	14% 6% 2 5% 4 3 4 3 7% 7% 44%	2888
	21st to end	Night	13% 7% 2 7% 5% 4 5% 3 6% 7% 43%	3452
September	1st to 10th	Night	9% 5% 2 5% 4 3 3 4 4 7% 53%	2000
	11th to 20th	Night	10% 5% 2 5% 4 3 4 3 5% 8% 51%	2000
	21st to end	Night	14% 4 2 5% 4 4 4 3 4 7% 48%	2287
October	1st to 10th	Night	14% 7% 2 5% 3 3 4 3 4 7% 48%	2400
	11th to 20th	Night	16% 10% 3 7% 5% 3 4 3 5% 6% 39%	2400
	21st to end	Night	18% 10% 3 7% 5% 4 4 4 5% 5% 34%	2722
November	1st to 10th	Night	14% 10% 3 7% 5% 4 5% 3 5% 7% 37%	2783
	11th to 20th	Night	15% 11% 6% 10% 5% 4 4 4 4 5% 32%	2940
	21st to end	Night	13% 10% 4 10% 6% 5% 4 3 5% 6% 34%	2940
December	1st to 10th	Night	7% 12% 5% 15% 9% 7% 5% 4 5% 7% 23%	4720
	11th to 20th	Night	12% 18% 6% 12% 6% 5% 5% 4 4 4 23%	5339
	21st to end	Night	23% 19% 6% 13% 5% 4 3 2 3 4 18%	7150

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	63% 4 8% 15% 9%	4692
	11th to 20th	Day	62% 5% 9% 14% 10%	4710
	21st to end	Day	51% 5% 13% 23% 8%	5630
February	1st to 10th	Day	51% 5% 13% 21% 9% 1	1890
	11th to 20th	Day	46% 6% 14% 25% 8% 1	1853
	21st to end	Day	51% 5% 12% 21% 10% 1	1636
March	1st to 10th	Day	40% 5% 17% 24% 11% 3	4815
	11th to 20th	Day	44% 5% 15% 26% 10% 1	5090
	21st to end	Day	55% 6% 8% 20% 9% 1	5720
April	1st to 10th	Day	52% 5% 11% 18% 12% 1	2520
	11th to 20th	Day	55% 5% 10% 17% 11% 1	2446
	21st to end	Day	56% 6% 10% 19% 9%	2596
May	1st to 10th	Day	37% 6% 13% 27% 16% 2	6307
	11th to 20th	Day	44% 6% 12% 20% 13% 5%	6323
	21st to end	Day	44% 7% 9% 27% 12% 1	6949
June	1st to 10th	Day	36% 7% 16% 29% 11% 1	2800
	11th to 20th	Day	44% 7% 15% 21% 12% 1	2800
	21st to end	Day	37% 8% 18% 26% 9% 1	2996
July	1st to 10th	Day	33% 5% 19% 33% 9%	6389
	11th to 20th	Day	29% 4 17% 36% 13% 1	6285
	21st to end	Day	32% 5% 17% 30% 15%	6728
August	1st to 10th	Day	38% 6% 15% 26% 13% 1	4302
	11th to 20th	Day	39% 6% 13% 33% 9%	4210
	21st to end	Day	41% 5% 17% 25% 11% 1	4448
September	1st to 10th	Day	36% 7% 15% 32% 10%	2400
	11th to 20th	Day	37% 8% 19% 28% 7%	2400
	21st to end	Day	39% 6% 13% 32% 9% 1	2090
October	1st to 10th	Day	31% 5% 10% 36% 17%	3260
	11th to 20th	Day	43% 4 9% 26% 16% 2	3240
	21st to end	Day	48% 4 16% 24% 8%	3394
November	1st to 10th	Day	51% 6% 13% 19% 11% 1	1732
	11th to 20th	Day	58% 6% 13% 16% 6% 1	1680
	21st to end	Day	54% 6% 15% 18% 5% 2	1680
December	1st to 10th	Day	67% 4 11% 13% 3 1	2690
	11th to 20th	Day	58% 6% 9% 17% 10%	3085
	21st to end	Day	78% 4 6% 7% 5%	4070
January	1st to 10th	Night	59% 4 13% 15% 10%	8233
	11th to 20th	Night	62% 5% 9% 15% 9%	8280
	21st to end	Night	51% 4 11% 23% 10%	8582
February	1st to 10th	Night	49% 6% 12% 21% 10% 1	2730
	11th to 20th	Night	47% 6% 13% 23% 9% 1	2664
	21st to end	Night	51% 6% 13% 20% 10% 1	2168
March	1st to 10th	Night	38% 4 15% 21% 17% 4	5287
	11th to 20th	Night	47% 5% 14% 22% 12%	5090
	21st to end	Night	59% 3 10% 14% 13%	5452
April	1st to 10th	Night	50% 6% 7% 19% 16% 1	2100
	11th to 20th	Night	51% 5% 9% 21% 13% 2	2035
	21st to end	Night	50% 7% 9% 19% 14% 1	1800
May	1st to 10th	Night	36% 6% 11% 27% 18% 1	3671
	11th to 20th	Night	35% 5% 12% 23% 18% 7%	3597
	21st to end	Night	42% 7% 11% 26% 13% 1	3950
June	1st to 10th	Night	35% 8% 15% 27% 12% 2	1600
	11th to 20th	Night	38% 7% 16% 20% 19% 1	1592
	21st to end	Night	33% 10% 15% 28% 13% 3	1400
July	1st to 10th	Night	30% 5% 20% 33% 11% 1	3448
	11th to 20th	Night	28% 5% 15% 37% 13% 2	3572
	21st to end	Night	35% 5% 14% 29% 16% 1	3832
August	1st to 10th	Night	34% 5% 15% 27% 16% 3	2817
	11th to 20th	Night	37% 6% 13% 32% 11% 1	2915
	21st to end	Night	41% 5% 16% 27% 10% 1	3452
September	1st to 10th	Night	30% 8% 14% 34% 13% 1	2000
	11th to 20th	Night	31% 6% 18% 32% 12%	2000
	21st to end	Night	37% 5% 13% 32% 13% 1	2287
October	1st to 10th	Night	26% 3 8% 36% 23% 4	3920
	11th to 20th	Night	39% 5% 11% 23% 21% 1	3899
	21st to end	Night	49% 4 12% 24% 11%	4395
November	1st to 10th	Night	46% 6% 13% 23% 11% 1	2783
	11th to 20th	Night	54% 5% 13% 18% 9% 1	2940
	21st to end	Night	50% 7% 16% 21% 6% 1	2940
December	1st to 10th	Night	60% 6% 15% 16% 3	4720
	11th to 20th	Night	63% 5% 9% 15% 7%	5341
	21st to end	Night	71% 4 7% 12% 5%	7150

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	13% 9% 38% 28% 8% 4	330
	11th to 20th	Day	14% 10% 39% 30% 7%	330
	21st to end	Day	13% 10% 42% 20% 13% 1	363
February	1st to 10th	Day	15% 14% 43% 22% 4 2	330
	11th to 20th	Day	12% 15% 42% 22% 7% 2	330
	21st to end	Day	15% 15% 44% 22% 3	273
March	1st to 10th	Day	18% 14% 39% 20% 8% 1	330
	11th to 20th	Day	18% 12% 41% 21% 7% 2	330
	21st to end	Day	25% 13% 31% 19% 9% 2	421
April	1st to 10th	Day	22% 15% 35% 21% 6%	540
	11th to 20th	Day	27% 11% 30% 23% 9% 1	516
	21st to end	Day	26% 11% 31% 21% 9% 2	696
May	1st to 10th	Day	18% 15% 28% 25% 11% 3	703
	11th to 20th	Day	20% 12% 27% 26% 12% 4	725
	21st to end	Day	18% 11% 25% 24% 18% 4	789
June	1st to 10th	Day	12% 6% 29% 30% 18% 4	730
	11th to 20th	Day	13% 9% 36% 29% 11% 2	730
	21st to end	Day	14% 7% 31% 27% 15% 6%	730
July	1st to 10th	Day	8% 3 21% 32% 24% 11%	721
	11th to 20th	Day	9% 5% 27% 27% 21% 10%	718
	21st to end	Day	7% 3 27% 34% 22% 7%	794
August	1st to 10th	Day	10% 5% 23% 32% 23% 6%	726
	11th to 20th	Day	15% 5% 19% 30% 23% 7%	715
	21st to end	Day	12% 7% 22% 31% 23% 5%	668
September	1st to 10th	Day	12% 6% 27% 32% 17% 5%	530
	11th to 20th	Day	12% 5% 27% 31% 20% 4	530
	21st to end	Day	20% 9% 28% 18% 19% 7%	345
October	1st to 10th	Day	17% 11% 31% 21% 13% 8%	330
	11th to 20th	Day	20% 18% 31% 25% 5% 1	330
	21st to end	Day	24% 13% 37% 17% 7% 1	363
November	1st to 10th	Day	20% 13% 37% 21% 8% 2	330
	11th to 20th	Day	18% 18% 36% 19% 8%	330
	21st to end	Day	22% 12% 36% 24% 6%	330
December	1st to 10th	Day	15% 12% 38% 25% 10%	330
	11th to 20th	Day	21% 15% 37% 22% 5%	330
	21st to end	Day	28% 12% 36% 20% 4 1	363
January	1st to 10th	Night	13% 10% 35% 32% 9% 1	1050
	11th to 20th	Night	16% 8% 38% 29% 7% 1	1050
	21st to end	Night	16% 9% 37% 31% 7% 1	1155
February	1st to 10th	Night	13% 9% 40% 30% 8%	1050
	11th to 20th	Night	10% 10% 41% 30% 8% 1	1029
	21st to end	Night	17% 11% 35% 30% 8% 1	784
March	1st to 10th	Night	16% 11% 35% 29% 7% 1	751
	11th to 20th	Night	19% 8% 40% 27% 6%	630
	21st to end	Night	21% 11% 30% 28% 9% 2	693
April	1st to 10th	Night	23% 11% 32% 28% 6%	630
	11th to 20th	Night	26% 9% 30% 27% 8% 1	611
	21st to end	Night	25% 7% 29% 31% 8% 1	600
May	1st to 10th	Night	18% 10% 33% 32% 7% 1	600
	11th to 20th	Night	16% 7% 32% 32% 12% 2	591
	21st to end	Night	15% 6% 27% 38% 14%	650
June	1st to 10th	Night	12% 5% 30% 40% 12% 1	600
	11th to 20th	Night	13% 3 31% 43% 10%	600
	21st to end	Night	12% 5% 23% 42% 17% 1	600
July	1st to 10th	Night	6% 3 21% 42% 26% 2	585
	11th to 20th	Night	8% 2 27% 41% 21% 1	582
	21st to end	Night	6% 3 19% 46% 23% 2	657
August	1st to 10th	Night	8% 3 15% 52% 21% 1	597
	11th to 20th	Night	14% 4 18% 36% 26% 2	594
	21st to end	Night	13% 3 20% 38% 23% 2	660
September	1st to 10th	Night	11% 4 24% 39% 19% 3	600
	11th to 20th	Night	12% 4 26% 39% 18% 2	600
	21st to end	Night	15% 8% 31% 28% 17% 1	705
October	1st to 10th	Night	20% 8% 27% 31% 12% 2	800
	11th to 20th	Night	20% 11% 34% 29% 6%	800
	21st to end	Night	24% 9% 29% 31% 8%	880
November	1st to 10th	Night	19% 9% 35% 30% 7%	937
	11th to 20th	Night	20% 12% 32% 28% 8%	1050
	21st to end	Night	18% 12% 37% 26% 7%	1050
December	1st to 10th	Night	17% 11% 32% 31% 8% 1	1050
	11th to 20th	Night	20% 10% 36% 25% 8% 1	1050
	21st to end	Night	26% 8% 33% 26% 6% 1	1155

Page generated at 2026-04-14 01:44:25. Version ac07

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