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 2024-07-16.

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% 10% 3 8% 5% 5% 5% 4 5% 7% 36%	90078
	Night	13% 11% 4 8% 5% 4 4 3 5% 6% 36%	89434
Transparency	Day	46% 7% 13% 22% 10% 1	89832
	Night	47% 7% 13% 22% 11% 1	89285
Seeing	Day	16% 10% 31% 26% 14% 4	15632
	Night	16% 8% 31% 32% 11% 1	25560

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	12% 16% 8% 13% 6% 4 4 3 5% 5% 24%	2527
	11th to 20th	Day	6% 11% 5% 15% 9% 11% 9% 6% 5% 5% 18%	2530
	21st to end	Day	8% 20% 8% 13% 5% 5% 5% 4 5% 5% 21%	3037
February	1st to 10th	Day	9% 12% 4 10% 6% 5% 4 4 4 8% 34%	1710
	11th to 20th	Day	8% 12% 5% 8% 6% 5% 5% 4 6% 7% 35%	1664
	21st to end	Day	11% 12% 3 11% 6% 5% 5% 2 5% 7% 33%	1484
March	1st to 10th	Day	10% 13% 3 8% 5% 4 4 4 5% 6% 39%	3280
	11th to 20th	Day	9% 9% 3 9% 5% 5% 4 4 5% 7% 39%	3480
	21st to end	Day	20% 13% 4 9% 5% 4 5% 3 5% 5% 25%	3904
April	1st to 10th	Day	16% 11% 4 9% 5% 4 5% 4 5% 6% 33%	2280
	11th to 20th	Day	20% 12% 3 8% 4 4 4 3 5% 6% 31%	2254
	21st to end	Day	22% 10% 3 8% 5% 5% 5% 3 4 6% 30%	2466
May	1st to 10th	Day	17% 7% 2 7% 4 4 4 3 5% 7% 38%	4362
	11th to 20th	Day	15% 6% 3 6% 5% 4 5% 4 5% 6% 42%	4399
	21st to end	Day	18% 8% 3 7% 4 5% 5% 4 5% 7% 34%	4824
June	1st to 10th	Day	12% 5% 2 5% 5% 4 4 4 6% 8% 45%	2660
	11th to 20th	Day	13% 7% 2 7% 6% 5% 4 4 6% 8% 38%	2660
	21st to end	Day	11% 5% 2 6% 5% 5% 5% 5% 8% 10% 38%	2846
July	1st to 10th	Day	6% 4 2 4 4 4 5% 5% 7% 10% 48%	2708
	11th to 20th	Day	9% 5% 2 6% 4 4 4 4 6% 9% 48%	2593
	21st to end	Day	8% 4 2 5% 4 4 5% 5% 7% 9% 48%	2743
August	1st to 10th	Day	9% 5% 2 7% 5% 5% 6% 5% 6% 9% 42%	2380
	11th to 20th	Day	13% 5% 2 6% 4 4 5% 3 5% 7% 44%	2301
	21st to end	Day	11% 5% 2 6% 4 3 4 3 5% 8% 49%	2453
September	1st to 10th	Day	11% 5% 2 6% 4 4 5% 4 6% 8% 44%	2160
	11th to 20th	Day	13% 5% 2 7% 4 4 4 4 5% 7% 44%	2160
	21st to end	Day	17% 7% 2 6% 4 4 4 3 5% 8% 40%	1882
October	1st to 10th	Day	18% 8% 2 6% 4 3 4 4 7% 7% 37%	1800
	11th to 20th	Day	18% 12% 3 7% 5% 4 5% 3 4 5% 34%	1800
	21st to end	Day	20% 12% 3 6% 6% 5% 4 3 4 6% 33%	1906
November	1st to 10th	Day	13% 13% 3 9% 5% 4 4 4 5% 7% 34%	1564
	11th to 20th	Day	13% 15% 6% 12% 6% 5% 4 4 5% 6% 25%	1520
	21st to end	Day	15% 13% 3 9% 4 3 5% 3 5% 6% 33%	1520
December	1st to 10th	Day	10% 15% 6% 13% 9% 4 6% 4 4 6% 22%	1520
	11th to 20th	Day	13% 14% 7% 12% 6% 5% 3 4 5% 5% 25%	1918
	21st to end	Day	25% 17% 5% 13% 6% 4 3 2 3 4 18%	2783
January	1st to 10th	Night	13% 12% 8% 14% 6% 4 4 3 4 5% 28%	4428
	11th to 20th	Night	6% 11% 5% 14% 9% 8% 8% 5% 6% 5% 22%	4440
	21st to end	Night	9% 23% 8% 12% 6% 4 4 3 4 5% 23%	4628
February	1st to 10th	Night	6% 11% 5% 10% 6% 5% 5% 3 5% 6% 36%	2470
	11th to 20th	Night	6% 11% 4 10% 6% 5% 4 4 6% 5% 37%	2403
	21st to end	Night	12% 12% 3 8% 6% 5% 5% 3 5% 5% 35%	1968
March	1st to 10th	Night	9% 8% 3 7% 5% 4 4 3 5% 6% 46%	3587
	11th to 20th	Night	8% 10% 3 11% 5% 5% 4 4 5% 5% 40%	3480
	21st to end	Night	23% 14% 5% 10% 4 3 3 2 4 4 29%	3726
April	1st to 10th	Night	19% 10% 3 6% 5% 4 3 3 5% 5% 36%	1900
	11th to 20th	Night	22% 10% 3 6% 4 4 3 3 4 4 36%	1875
	21st to end	Night	20% 10% 3 7% 4 4 4 4 5% 6% 33%	1710
May	1st to 10th	Night	15% 8% 3 7% 5% 4 5% 3 5% 7% 38%	2543
	11th to 20th	Night	14% 6% 2 4 3 3 4 3 5% 8% 48%	2506
	21st to end	Night	14% 8% 3 7% 5% 4 4 4 6% 7% 38%	2743
June	1st to 10th	Night	11% 5% 2 6% 5% 5% 5% 4 6% 10% 43%	1520
	11th to 20th	Night	11% 5% 2 5% 5% 5% 5% 3 7% 7% 44%	1513
	21st to end	Night	8% 6% 2 6% 4 5% 5% 4 7% 7% 46%	1330
July	1st to 10th	Night	5% 4 2 4 4 4 4 4 7% 9% 54%	1463
	11th to 20th	Night	7% 5% 2 5% 4 3 5% 4 6% 8% 51%	1488
	21st to end	Night	5% 3 2 4 3 3 4 4 7% 8% 58%	1575
August	1st to 10th	Night	6% 5% 2 5% 4 3 4 4 6% 10% 51%	1556
	11th to 20th	Night	14% 6% 2 5% 4 3 4 3 6% 6% 49%	1600
	21st to end	Night	11% 4 2 5% 5% 4 4 2 5% 6% 51%	1902
September	1st to 10th	Night	9% 5% 2 5% 4 4 4 4 4 7% 52%	1800
	11th to 20th	Night	10% 5% 1 5% 4 3 3 4 5% 8% 53%	1800
	21st to end	Night	16% 5% 2 5% 4 4 4 3 4 7% 45%	2057
October	1st to 10th	Night	16% 7% 2 5% 3 3 4 3 4 7% 45%	2160
	11th to 20th	Night	16% 10% 3 7% 4 3 4 3 4 6% 38%	2160
	21st to end	Night	18% 10% 4 7% 4 4 4 4 5% 5% 34%	2449
November	1st to 10th	Night	15% 10% 3 7% 5% 4 5% 3 5% 7% 38%	2511
	11th to 20th	Night	15% 11% 6% 10% 5% 4 4 4 4 6% 31%	2660
	21st to end	Night	13% 10% 4 8% 5% 5% 4 4 5% 6% 36%	2660
December	1st to 10th	Night	10% 15% 5% 11% 8% 5% 5% 4 5% 7% 26%	2660
	11th to 20th	Night	12% 17% 5% 11% 7% 6% 5% 4 4 5% 25%	3279
	21st to end	Night	24% 20% 4 9% 5% 4 3 2 3 5% 21%	4884

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	61% 8% 10% 17% 4	2528
	11th to 20th	Day	64% 8% 9% 14% 5%	2530
	21st to end	Day	62% 8% 11% 15% 4	3037
February	1st to 10th	Day	50% 6% 13% 22% 9% 1	1710
	11th to 20th	Day	47% 7% 14% 24% 8% 1	1673
	21st to end	Day	52% 6% 11% 20% 11% 1	1484
March	1st to 10th	Day	45% 7% 14% 22% 11% 1	3280
	11th to 20th	Day	42% 7% 14% 27% 10% 1	3480
	21st to end	Day	59% 8% 8% 20% 5%	3904
April	1st to 10th	Day	51% 6% 12% 18% 12% 1	2280
	11th to 20th	Day	54% 5% 9% 18% 12% 1	2254
	21st to end	Day	56% 6% 10% 19% 9%	2466
May	1st to 10th	Day	43% 8% 12% 24% 12% 1	4403
	11th to 20th	Day	40% 8% 14% 24% 12% 2	4403
	21st to end	Day	47% 9% 12% 22% 10% 1	4837
June	1st to 10th	Day	35% 7% 17% 29% 11% 1	2660
	11th to 20th	Day	43% 7% 15% 22% 13% 1	2660
	21st to end	Day	37% 9% 19% 26% 9% 1	2846
July	1st to 10th	Day	28% 9% 17% 30% 15%	2639
	11th to 20th	Day	31% 9% 16% 26% 16% 2	2518
	21st to end	Day	29% 9% 18% 28% 15% 1	2591
August	1st to 10th	Day	35% 9% 17% 27% 9% 3	2365
	11th to 20th	Day	38% 8% 15% 28% 11%	2301
	21st to end	Day	33% 8% 14% 30% 14% 2	2453
September	1st to 10th	Day	36% 8% 14% 31% 10%	2160
	11th to 20th	Day	36% 9% 18% 29% 7%	2160
	21st to end	Day	42% 7% 14% 31% 7%	1882
October	1st to 10th	Day	42% 8% 14% 27% 8%	1800
	11th to 20th	Day	52% 7% 11% 19% 10% 1	1800
	21st to end	Day	52% 6% 13% 21% 8%	1906
November	1st to 10th	Day	50% 7% 13% 19% 11% 1	1564
	11th to 20th	Day	60% 7% 13% 14% 7% 1	1520
	21st to end	Day	51% 7% 16% 19% 5% 2	1520
December	1st to 10th	Day	63% 7% 14% 13% 4	1520
	11th to 20th	Day	59% 8% 13% 15% 4 1	1915
	21st to end	Day	71% 5% 8% 9% 7%	2783
January	1st to 10th	Night	58% 6% 12% 18% 6% 1	4428
	11th to 20th	Night	60% 8% 13% 13% 5%	4440
	21st to end	Night	63% 6% 9% 16% 5%	4628
February	1st to 10th	Night	47% 7% 12% 22% 10% 1	2470
	11th to 20th	Night	46% 7% 14% 23% 8% 1	2404
	21st to end	Night	51% 6% 13% 20% 10% 1	1968
March	1st to 10th	Night	38% 6% 14% 24% 16% 2	3587
	11th to 20th	Night	44% 7% 11% 25% 13%	3480
	21st to end	Night	60% 4 8% 17% 10%	3726
April	1st to 10th	Night	49% 7% 8% 18% 16% 2	1900
	11th to 20th	Night	51% 5% 7% 21% 14% 2	1875
	21st to end	Night	49% 7% 9% 19% 13% 1	1710
May	1st to 10th	Night	43% 8% 12% 20% 16% 1	2567
	11th to 20th	Night	33% 7% 11% 28% 19% 3	2507
	21st to end	Night	40% 10% 14% 22% 13% 1	2751
June	1st to 10th	Night	34% 9% 16% 27% 12% 2	1520
	11th to 20th	Night	36% 7% 16% 20% 20% 2	1513
	21st to end	Night	32% 10% 15% 28% 13% 3	1330
July	1st to 10th	Night	24% 9% 17% 32% 17% 1	1423
	11th to 20th	Night	29% 8% 13% 31% 15% 4	1440
	21st to end	Night	21% 9% 17% 31% 18% 3	1487
August	1st to 10th	Night	27% 8% 16% 30% 14% 5%	1547
	11th to 20th	Night	33% 8% 16% 27% 15% 2	1600
	21st to end	Night	33% 6% 13% 28% 17% 2	1902
September	1st to 10th	Night	30% 8% 14% 33% 14% 1	1800
	11th to 20th	Night	30% 7% 17% 33% 13%	1800
	21st to end	Night	39% 6% 13% 31% 11% 1	2057
October	1st to 10th	Night	39% 6% 12% 30% 12% 2	2160
	11th to 20th	Night	46% 8% 12% 23% 11% 1	2160
	21st to end	Night	49% 7% 13% 20% 9% 1	2449
November	1st to 10th	Night	46% 6% 13% 23% 11% 1	2511
	11th to 20th	Night	55% 6% 13% 16% 9%	2660
	21st to end	Night	48% 7% 17% 21% 6% 1	2660
December	1st to 10th	Night	57% 7% 14% 16% 5%	2660
	11th to 20th	Night	59% 8% 12% 16% 5% 1	3281
	21st to end	Night	67% 6% 10% 14% 4	4884

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	14% 10% 37% 26% 9% 4	270
	11th to 20th	Day	14% 10% 39% 29% 8%	270
	21st to end	Day	15% 9% 40% 20% 14% 2	297
February	1st to 10th	Day	15% 13% 43% 23% 5% 1	270
	11th to 20th	Day	13% 18% 43% 18% 6% 3	270
	21st to end	Day	16% 14% 44% 22% 3	225
March	1st to 10th	Day	19% 15% 36% 20% 9% 1	270
	11th to 20th	Day	17% 12% 39% 22% 8% 2	270
	21st to end	Day	25% 13% 30% 20% 10% 2	349
April	1st to 10th	Day	22% 15% 35% 21% 7%	460
	11th to 20th	Day	26% 11% 29% 23% 10% 1	452
	21st to end	Day	26% 11% 31% 20% 10% 2	646
May	1st to 10th	Day	19% 16% 30% 25% 9% 2	653
	11th to 20th	Day	18% 12% 28% 27% 12% 4	675
	21st to end	Day	18% 11% 26% 24% 17% 4	734
June	1st to 10th	Day	11% 7% 29% 31% 18% 5%	680
	11th to 20th	Day	12% 9% 36% 29% 11% 2	680
	21st to end	Day	13% 7% 30% 28% 16% 6%	680
July	1st to 10th	Day	9% 4 21% 31% 25% 11%	671
	11th to 20th	Day	9% 6% 27% 28% 21% 9%	645
	21st to end	Day	7% 3 26% 35% 21% 8%	684
August	1st to 10th	Day	9% 5% 23% 34% 24% 6%	626
	11th to 20th	Day	14% 6% 19% 32% 22% 7%	615
	21st to end	Day	11% 8% 24% 31% 22% 5%	572
September	1st to 10th	Day	12% 6% 27% 33% 17% 5%	450
	11th to 20th	Day	12% 6% 29% 30% 20% 4	450
	21st to end	Day	24% 11% 29% 19% 13% 5%	284
October	1st to 10th	Day	19% 10% 31% 19% 14% 8%	270
	11th to 20th	Day	19% 19% 31% 25% 6% 1	270
	21st to end	Day	24% 14% 40% 13% 8% 1	297
November	1st to 10th	Day	20% 13% 36% 21% 9% 2	270
	11th to 20th	Day	19% 17% 37% 20% 7%	270
	21st to end	Day	22% 12% 39% 21% 6%	270
December	1st to 10th	Day	15% 13% 38% 23% 10%	270
	11th to 20th	Day	22% 15% 36% 21% 6%	270
	21st to end	Day	27% 13% 37% 21% 2	297
January	1st to 10th	Night	13% 11% 35% 31% 9% 1	950
	11th to 20th	Night	17% 7% 38% 29% 8% 1	950
	21st to end	Night	17% 8% 36% 31% 7% 1	1045
February	1st to 10th	Night	12% 9% 40% 30% 8%	950
	11th to 20th	Night	10% 11% 40% 30% 8% 1	929
	21st to end	Night	18% 10% 34% 29% 8% 1	712
March	1st to 10th	Night	16% 11% 35% 29% 8% 1	679
	11th to 20th	Night	18% 8% 40% 28% 6%	570
	21st to end	Night	21% 11% 28% 27% 10% 2	627
April	1st to 10th	Night	22% 11% 33% 28% 6%	570
	11th to 20th	Night	26% 9% 29% 27% 8% 1	563
	21st to end	Night	24% 7% 29% 31% 8% 1	570
May	1st to 10th	Night	18% 11% 33% 31% 6% 1	570
	11th to 20th	Night	16% 7% 32% 32% 11% 2	561
	21st to end	Night	15% 6% 27% 37% 14%	617
June	1st to 10th	Night	11% 5% 30% 41% 12% 1	570
	11th to 20th	Night	12% 4 31% 43% 10%	570
	21st to end	Night	10% 5% 23% 42% 18% 1	570
July	1st to 10th	Night	6% 3 21% 42% 27% 2	555
	11th to 20th	Night	8% 3 28% 41% 20% 1	540
	21st to end	Night	5% 3 20% 47% 23% 2	591
August	1st to 10th	Night	6% 3 15% 53% 21% 1	537
	11th to 20th	Night	14% 4 19% 35% 26% 2	534
	21st to end	Night	12% 4 21% 37% 24% 2	594
September	1st to 10th	Night	10% 4 24% 39% 19% 4	540
	11th to 20th	Night	11% 4 28% 37% 18% 2	540
	21st to end	Night	16% 8% 33% 27% 15% 1	634
October	1st to 10th	Night	21% 8% 26% 31% 12% 2	720
	11th to 20th	Night	20% 12% 33% 29% 6%	720
	21st to end	Night	23% 9% 28% 31% 8%	792
November	1st to 10th	Night	19% 9% 34% 29% 7%	845
	11th to 20th	Night	19% 12% 32% 28% 8%	950
	21st to end	Night	18% 12% 37% 26% 7%	950
December	1st to 10th	Night	17% 11% 31% 31% 8% 1	950
	11th to 20th	Night	21% 9% 37% 25% 8% 1	950
	21st to end	Night	26% 9% 34% 25% 6%	1045

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