Red Deer
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Red Deer clear sky chart from 2005-11-06 to 2024-03-23.

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	10% 9% 4 7% 7% 4 6% 6% 6% 9% 34%	78110
	Night	7% 10% 5% 8% 7% 4 6% 6% 6% 8% 33%	81740
Transparency	Day	45% 8% 17% 22% 8% 1	77813
	Night	46% 7% 14% 21% 9% 2	81618
Seeing	Day	12% 6% 25% 32% 19% 6%	14455
	Night	12% 6% 29% 37% 15% 2	23742

By Month

Percentage Cloud Cover NW (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 11% 6% 10% 9% 5% 6% 6% 7% 7% 30%	2219
	11th to 20th	Day	5% 8% 5% 10% 7% 4 7% 9% 8% 9% 29%	2199
	21st to end	Day	5% 10% 4 8% 8% 4 5% 5% 5% 9% 37%	2734
February	1st to 10th	Day	8% 13% 6% 9% 7% 5% 6% 5% 6% 9% 28%	1520
	11th to 20th	Day	6% 12% 7% 11% 9% 4 6% 6% 6% 7% 26%	1630
	21st to end	Day	4 10% 7% 11% 10% 5% 7% 7% 6% 7% 25%	1498
March	1st to 10th	Day	6% 12% 7% 12% 10% 5% 6% 6% 6% 8% 24%	1900
	11th to 20th	Day	7% 10% 5% 8% 7% 3 6% 5% 8% 11% 32%	2063
	21st to end	Day	9% 13% 6% 8% 8% 5% 6% 5% 7% 8% 25%	2232
April	1st to 10th	Day	9% 10% 5% 8% 8% 4 6% 6% 7% 8% 28%	2227
	11th to 20th	Day	12% 13% 4 9% 7% 3 6% 5% 6% 8% 27%	2310
	21st to end	Day	12% 10% 4 7% 7% 4 5% 5% 6% 9% 31%	2340
May	1st to 10th	Day	12% 12% 3 8% 6% 4 6% 6% 7% 8% 28%	2550
	11th to 20th	Day	8% 7% 3 7% 7% 3 5% 5% 7% 9% 39%	2654
	21st to end	Day	18% 7% 3 6% 6% 3 5% 5% 7% 7% 32%	2917
June	1st to 10th	Day	16% 6% 3 7% 6% 4 6% 6% 7% 9% 30%	2700
	11th to 20th	Day	20% 8% 4 7% 6% 4 6% 6% 6% 8% 24%	2700
	21st to end	Day	10% 5% 2 5% 6% 4 7% 7% 8% 10% 37%	2700
July	1st to 10th	Day	10% 6% 2 5% 5% 3 5% 6% 7% 10% 39%	2700
	11th to 20th	Day	12% 5% 2 4 5% 3 6% 6% 7% 10% 40%	2700
	21st to end	Day	8% 4 2 4 5% 4 5% 5% 7% 9% 47%	2938
August	1st to 10th	Day	10% 5% 2 5% 5% 3 5% 7% 7% 10% 40%	2507
	11th to 20th	Day	10% 4 2 4 5% 3 5% 6% 6% 9% 47%	2350
	21st to end	Day	10% 5% 2 5% 5% 3 5% 6% 7% 9% 43%	2574
September	1st to 10th	Day	12% 6% 2 5% 6% 3 5% 5% 6% 8% 42%	2261
	11th to 20th	Day	16% 7% 3 5% 4 3 3 3 7% 8% 41%	1980
	21st to end	Day	9% 8% 2 6% 5% 3 4 5% 6% 8% 43%	1980
October	1st to 10th	Day	13% 9% 3 7% 5% 3 4 5% 5% 6% 40%	1890
	11th to 20th	Day	11% 8% 4 6% 6% 4 6% 6% 6% 8% 37%	1654
	21st to end	Day	8% 11% 4 8% 8% 4 5% 6% 6% 6% 32%	1782
November	1st to 10th	Day	7% 15% 6% 8% 7% 4 6% 6% 6% 6% 27%	1511
	11th to 20th	Day	6% 13% 6% 9% 8% 3 5% 3 5% 8% 33%	1406
	21st to end	Day	5% 11% 4 9% 9% 5% 6% 5% 7% 9% 31%	1330
December	1st to 10th	Day	6% 13% 5% 10% 10% 6% 6% 4 4 7% 28%	1330
	11th to 20th	Day	4 11% 5% 11% 9% 5% 6% 7% 7% 7% 28%	1682
	21st to end	Day	4 8% 4 7% 7% 3 5% 4 6% 11% 41%	2442
January	1st to 10th	Night	3 13% 7% 11% 8% 5% 6% 6% 6% 8% 27%	4726
	11th to 20th	Night	4 9% 5% 11% 9% 5% 6% 8% 6% 7% 31%	4699
	21st to end	Night	4 12% 5% 9% 8% 4 6% 7% 6% 9% 31%	4954
February	1st to 10th	Night	6% 12% 5% 11% 8% 5% 5% 5% 6% 8% 29%	2660
	11th to 20th	Night	6% 12% 6% 10% 9% 4 6% 7% 6% 7% 26%	2436
	21st to end	Night	6% 10% 5% 9% 9% 4 7% 5% 6% 8% 32%	1955
March	1st to 10th	Night	5% 10% 5% 9% 10% 5% 7% 7% 7% 8% 27%	2280
	11th to 20th	Night	6% 8% 5% 9% 7% 4 6% 7% 8% 10% 29%	2115
	21st to end	Night	8% 13% 7% 11% 6% 4 5% 6% 6% 8% 26%	2165
April	1st to 10th	Night	8% 11% 4 8% 8% 5% 6% 7% 7% 7% 29%	1733
	11th to 20th	Night	9% 13% 5% 10% 8% 4 5% 5% 6% 7% 28%	1601
	21st to end	Night	10% 10% 4 6% 6% 4 6% 6% 6% 10% 31%	1620
May	1st to 10th	Night	15% 12% 5% 8% 6% 3 5% 7% 6% 7% 26%	1409
	11th to 20th	Night	10% 7% 4 6% 6% 5% 5% 6% 7% 9% 36%	1239
	21st to end	Night	18% 8% 4 7% 6% 3 6% 5% 6% 8% 29%	1358
June	1st to 10th	Night	18% 8% 4 7% 6% 3 6% 5% 7% 8% 28%	1260
	11th to 20th	Night	17% 9% 4 8% 7% 4 7% 6% 7% 7% 24%	1260
	21st to end	Night	8% 4 3 7% 7% 4 6% 7% 7% 10% 36%	1260
July	1st to 10th	Night	11% 5% 2 5% 6% 3 5% 6% 7% 12% 39%	1260
	11th to 20th	Night	10% 6% 3 6% 6% 4 5% 6% 8% 9% 38%	1260
	21st to end	Night	8% 3 2 5% 5% 3 5% 5% 8% 10% 46%	1379
August	1st to 10th	Night	10% 5% 2 6% 6% 4 7% 5% 7% 10% 38%	1429
	11th to 20th	Night	9% 7% 2 5% 4 3 5% 5% 7% 10% 41%	1549
	21st to end	Night	10% 5% 2 6% 5% 3 6% 6% 6% 9% 42%	1782
September	1st to 10th	Night	9% 6% 3 5% 5% 3 5% 6% 7% 8% 42%	1696
	11th to 20th	Night	14% 7% 3 5% 4 3 4 6% 5% 8% 41%	1980
	21st to end	Night	9% 6% 3 7% 5% 3 5% 5% 5% 9% 44%	1980
October	1st to 10th	Night	10% 8% 4 7% 6% 4 5% 5% 5% 7% 40%	2070
	11th to 20th	Night	9% 9% 3 7% 7% 4 5% 5% 6% 8% 37%	2304
	21st to end	Night	7% 11% 5% 8% 7% 4 6% 5% 6% 8% 32%	2574
November	1st to 10th	Night	9% 14% 6% 9% 6% 3 5% 6% 6% 7% 29%	2549
	11th to 20th	Night	7% 11% 6% 10% 8% 5% 6% 5% 6% 8% 29%	2774
	21st to end	Night	5% 10% 5% 9% 8% 4 6% 6% 7% 9% 31%	2850
December	1st to 10th	Night	7% 11% 5% 11% 8% 4 5% 5% 5% 8% 31%	2850
	11th to 20th	Night	3 11% 6% 12% 9% 5% 6% 6% 6% 9% 28%	3510
	21st to end	Night	3 9% 4 7% 7% 4 4 5% 6% 8% 43%	5214

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	50% 6% 13% 20% 10% 1	2219
	11th to 20th	Day	47% 7% 11% 14% 17% 4	2220
	21st to end	Day	42% 7% 15% 28% 7%	2734
February	1st to 10th	Day	52% 5% 14% 17% 11% 1	1520
	11th to 20th	Day	56% 7% 12% 16% 8% 1	1639
	21st to end	Day	55% 6% 11% 19% 9%	1498
March	1st to 10th	Day	56% 8% 13% 16% 6% 1	1900
	11th to 20th	Day	43% 6% 15% 22% 12% 1	2064
	21st to end	Day	54% 7% 17% 16% 6% 1	2232
April	1st to 10th	Day	51% 9% 15% 17% 8% 1	2227
	11th to 20th	Day	53% 7% 12% 20% 9% 1	2310
	21st to end	Day	49% 8% 14% 21% 5% 2	2340
May	1st to 10th	Day	50% 8% 15% 20% 7%	2550
	11th to 20th	Day	39% 8% 18% 24% 11%	2658
	21st to end	Day	48% 7% 15% 21% 8%	2918
June	1st to 10th	Day	48% 7% 17% 21% 6%	2700
	11th to 20th	Day	55% 9% 14% 17% 4 1	2700
	21st to end	Day	38% 11% 21% 24% 5% 1	2700
July	1st to 10th	Day	38% 8% 24% 23% 5% 1	2626
	11th to 20th	Day	39% 10% 22% 25% 4	2619
	21st to end	Day	31% 9% 25% 29% 6%	2775
August	1st to 10th	Day	36% 11% 22% 26% 5%	2490
	11th to 20th	Day	31% 9% 28% 24% 9% 1	2350
	21st to end	Day	34% 9% 21% 26% 9% 1	2574
September	1st to 10th	Day	38% 7% 20% 24% 8% 3	2261
	11th to 20th	Day	40% 7% 15% 28% 9% 1	1980
	21st to end	Day	38% 8% 16% 25% 11% 3	1980
October	1st to 10th	Day	45% 5% 17% 23% 9% 1	1890
	11th to 20th	Day	43% 7% 17% 23% 10% 1	1654
	21st to end	Day	48% 7% 12% 22% 10% 1	1782
November	1st to 10th	Day	54% 8% 13% 16% 7% 1	1511
	11th to 20th	Day	50% 6% 14% 20% 9% 1	1406
	21st to end	Day	47% 8% 18% 18% 7% 2	1330
December	1st to 10th	Day	56% 6% 11% 16% 8% 2	1330
	11th to 20th	Day	50% 9% 16% 19% 6% 1	1684
	21st to end	Day	38% 5% 12% 22% 18% 4	2442
January	1st to 10th	Night	53% 7% 11% 19% 8% 2	4726
	11th to 20th	Night	50% 6% 11% 15% 14% 4	4740
	21st to end	Night	47% 8% 13% 23% 8% 1	4954
February	1st to 10th	Night	53% 7% 10% 19% 10% 1	2660
	11th to 20th	Night	54% 6% 12% 15% 11% 1	2437
	21st to end	Night	49% 6% 12% 21% 11% 2	1955
March	1st to 10th	Night	52% 8% 13% 20% 6% 1	2280
	11th to 20th	Night	45% 8% 15% 20% 11% 1	2115
	21st to end	Night	54% 6% 14% 18% 7% 1	2165
April	1st to 10th	Night	49% 8% 15% 18% 9% 1	1733
	11th to 20th	Night	52% 6% 12% 22% 7% 1	1601
	21st to end	Night	44% 9% 16% 22% 8% 1	1620
May	1st to 10th	Night	52% 7% 14% 19% 7% 1	1409
	11th to 20th	Night	44% 8% 12% 21% 15%	1239
	21st to end	Night	50% 7% 16% 18% 8% 1	1358
June	1st to 10th	Night	53% 9% 14% 18% 7%	1260
	11th to 20th	Night	55% 9% 14% 15% 5% 1	1260
	21st to end	Night	40% 8% 20% 23% 7% 1	1260
July	1st to 10th	Night	36% 10% 24% 24% 5% 1	1225
	11th to 20th	Night	38% 14% 21% 20% 6% 1	1218
	21st to end	Night	30% 11% 21% 30% 8%	1302
August	1st to 10th	Night	38% 11% 22% 23% 6%	1422
	11th to 20th	Night	35% 9% 19% 27% 8% 1	1549
	21st to end	Night	35% 8% 18% 25% 11% 1	1782
September	1st to 10th	Night	36% 9% 15% 27% 11% 3	1696
	11th to 20th	Night	40% 7% 14% 26% 9% 3	1980
	21st to end	Night	37% 6% 16% 25% 13% 3	1980
October	1st to 10th	Night	43% 6% 16% 22% 12% 1	2070
	11th to 20th	Night	44% 6% 17% 22% 10% 2	2304
	21st to end	Night	47% 8% 16% 20% 8% 1	2574
November	1st to 10th	Night	52% 6% 12% 20% 8% 2	2549
	11th to 20th	Night	50% 6% 14% 19% 10% 1	2774
	21st to end	Night	47% 7% 18% 19% 7% 2	2850
December	1st to 10th	Night	51% 6% 11% 20% 10% 2	2850
	11th to 20th	Night	50% 8% 15% 21% 6%	3507
	21st to end	Night	37% 5% 12% 25% 15% 6%	5214

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	5% 6% 26% 35% 19% 9%	180
	11th to 20th	Day	6% 6% 37% 32% 16% 4	180
	21st to end	Day	7% 6% 33% 28% 20% 8%	198
February	1st to 10th	Day	11% 10% 22% 36% 16% 6%	180
	11th to 20th	Day	10% 6% 28% 39% 12% 6%	254
	21st to end	Day	5% 4 30% 35% 20% 6%	310
March	1st to 10th	Day	9% 8% 31% 32% 16% 4	460
	11th to 20th	Day	6% 5% 31% 35% 18% 5%	460
	21st to end	Day	14% 7% 29% 28% 17% 6%	471
April	1st to 10th	Day	10% 10% 32% 32% 11% 5%	420
	11th to 20th	Day	17% 8% 24% 28% 18% 5%	412
	21st to end	Day	16% 8% 24% 33% 14% 4	420
May	1st to 10th	Day	16% 9% 22% 31% 17% 5%	513
	11th to 20th	Day	10% 7% 24% 34% 21% 5%	625
	21st to end	Day	17% 4 18% 32% 22% 7%	679
June	1st to 10th	Day	19% 5% 21% 35% 16% 4	630
	11th to 20th	Day	22% 8% 21% 31% 16% 3	630
	21st to end	Day	11% 4 21% 33% 22% 10%	630
July	1st to 10th	Day	13% 4 17% 33% 23% 10%	621
	11th to 20th	Day	14% 4 18% 33% 25% 5%	618
	21st to end	Day	7% 5% 18% 33% 28% 9%	684
August	1st to 10th	Day	12% 6% 18% 32% 23% 9%	447
	11th to 20th	Day	9% 5% 19% 33% 28% 6%	437
	21st to end	Day	10% 8% 19% 31% 24% 9%	495
September	1st to 10th	Day	14% 6% 31% 26% 21% 3	450
	11th to 20th	Day	19% 6% 22% 29% 18% 4	450
	21st to end	Day	11% 12% 29% 27% 16% 5%	450
October	1st to 10th	Day	18% 6% 25% 28% 15% 9%	360
	11th to 20th	Day	11% 9% 33% 28% 14% 5%	270
	21st to end	Day	12% 10% 35% 29% 13% 1	297
November	1st to 10th	Day	14% 9% 28% 33% 12% 4	270
	11th to 20th	Day	12% 6% 32% 38% 12% 1	216
	21st to end	Day	4 6% 36% 32% 13% 9%	180
December	1st to 10th	Day	9% 6% 32% 32% 17% 5%	180
	11th to 20th	Day	7% 6% 39% 31% 16% 1	180
	21st to end	Day	9% 6% 23% 33% 23% 7%	198
January	1st to 10th	Night	10% 5% 36% 34% 14% 1	950
	11th to 20th	Night	12% 7% 33% 35% 12% 1	950
	21st to end	Night	11% 9% 30% 36% 12% 2	889
February	1st to 10th	Night	10% 9% 27% 36% 18% 1	760
	11th to 20th	Night	10% 6% 33% 35% 15%	744
	21st to end	Night	10% 4 24% 38% 20% 4	628
March	1st to 10th	Night	10% 4 31% 39% 15% 2	760
	11th to 20th	Night	9% 4 32% 39% 14% 3	760
	21st to end	Night	14% 5% 26% 39% 14% 3	800
April	1st to 10th	Night	12% 6% 32% 33% 16% 1	653
	11th to 20th	Night	14% 8% 26% 41% 9%	533
	21st to end	Night	15% 7% 29% 36% 13% 1	540
May	1st to 10th	Night	19% 8% 24% 35% 13% 1	419
	11th to 20th	Night	11% 6% 27% 38% 17% 1	354
	21st to end	Night	22% 4 22% 34% 16% 3	389
June	1st to 10th	Night	20% 6% 24% 36% 11% 3	360
	11th to 20th	Night	18% 5% 27% 33% 17%	360
	21st to end	Night	11% 3 23% 41% 21% 2	360
July	1st to 10th	Night	14% 1 15% 48% 21% 1	350
	11th to 20th	Night	14% 4 19% 41% 21% 1	348
	21st to end	Night	8% 5% 15% 41% 29% 2	394
August	1st to 10th	Night	13% 2 17% 33% 31% 3	358
	11th to 20th	Night	11% 5% 17% 42% 23% 2	481
	21st to end	Night	11% 4 21% 40% 24% 1	594
September	1st to 10th	Night	13% 3 24% 41% 17% 1	607
	11th to 20th	Night	18% 3 19% 39% 19% 1	720
	21st to end	Night	11% 4 29% 39% 16% 2	720
October	1st to 10th	Night	14% 4 26% 39% 15% 2	720
	11th to 20th	Night	12% 5% 32% 36% 14% 1	720
	21st to end	Night	12% 8% 33% 35% 12% 1	792
November	1st to 10th	Night	16% 8% 32% 33% 11% 1	884
	11th to 20th	Night	12% 8% 37% 31% 10% 2	950
	21st to end	Night	9% 4 38% 34% 12% 2	950
December	1st to 10th	Night	13% 7% 29% 34% 15% 3	950
	11th to 20th	Night	9% 6% 34% 36% 12% 2	950
	21st to end	Night	11% 4 32% 35% 15% 2	1045

Page generated at 2024-03-19 21:31:06. Version ac07

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