4:20 pm: It has just begun to rain and it's about 46 degrees. The forecast the next few days/nights is for rainy days in the mid-to-high 50's (not so bad), but 40-ish each night (not so good). The past few days have been off-and-on cold with cold nights. We've had some nice rain, so things are greening up. It's just frustrating not knowing when to plant or what's ok to plant.
I guess I'm getting more exposure to Colorado unpredictable weather. I know that May 15 is the "average" last frost date, meaning there's a good chance it will still be cold and/or frost after that date, but the last two years have been warmer and I've been too optimistic. Next year I will start things later and not plan on being able to plant by May 15, as I have the past two years.
I know that tomatoes and peppers need warm weather, and have heard not to plant them until it is consistently 50 overnight. However, I've had them out hardening off all week inside the cold frame, even the nights that were 30. It was just too difficult to carry them in and out each night & morning. Yesterday I went ahead and planted the tomatoes and today the peppers. I'm keeping the peppers covered, at least overnight, until it warms up--the cold frame fits nicely on top of the peppers and should keep them well protected. Some of the tomatoes have hoops over them and are ready to cover with frost cloth as need arises. So far, I'm leaving the tomatoes uncovered during the day. Not sure what to do with them overnight.
I've read that there is really no advantage to getting the tomatoes out too early--that bigger tomatoes grown inside and planted out early aren't ready to harvest any earlier than those done a little later and planted when warmer. Apparently warmth is the key, and it's possible that tomatoes planted in >40 degree weather won't produce as much fruit. We shall see. At any rate, next year I plan to start them later, and won't plan to plant them out as early. If there's really no advantage, why bother?